Qantas - Sydney to Singapore (picture from Creative Commons)
Singapore - Singapore to Melbourne (picture from Singapore Airlines)
All 3 airlines treat A380 suites the same as any other first class on the airline - ie pretty well. This means a dedicated first class check in lane (Qantas in Sydney & Melbourne, and Singapore in Singapore also have a special curbside first class check in lobby), priority immigration queue, access to a nice first class lounge (or combined business & first class lounge in the case of Emirates), as well as priority boarding together with business class and frequent flyer elite passengers. Emirates also has airport limo transfers at both ends for first and business class passengers on most routes (including trans-Tasman).
Qantas in Sydney and Melbourne, and Emirates in Sydney, also have a priority security queue for first class, business class and frequent flyer elite passengers. At Singapore security is processed at the gate, and the gates used by A380 do not have a priority lane.
Onboard all three airlines you are escorted to your seat, offered a pre-departure drink (juice, water and champagne are offered but in practice you can request other drinks as long as they don't take too long to prepare). On Singapore Airlines the champagne is a choice of Krug or Dom (2000 vintage currently), on Emirates it is Dom and on Qantas it varies. Emirates also offers a date and shot of Arabic coffee before departure.
Menus are handed out before departure. Other amenities (pajamas, slippers, toiletry kit) may be handed out before or after departure. Note due to the short flight duration, my Emirates flight did not offer pajamas or the normal amenity kit, but did include slippers and a small collection of creams.
On all three airlines noise cancelling headphones are used. Qantas has the headphones ready in a cubby hole but doesn't switch on the IFE (except for the tail camera) until well after take-off, Emirates hands out the headphones before departure so you can start watching movies straight away, whilst Singapore Airlines doesn't hand out headphones until after departure.
The hard product
All three airlines have a suite for first class - ie at least partially private with lie flat bed and ability for couples to dine together. Emirates and Singapore Airlines have a relatively similar set-up - in contrast Qantas is quite different.
On Qantas and Singapore Airlines, first class suites are on the lower deck, but on Emirates they are on the upper deck. Qantas has 1-1-1 layout across the cabin with seats angled to the direction of travel, Singapore Airlines and Emirates are 1-2-1 layout with seats facing forward. This means Qantas is not so good for couples travelling together, Singapore Airlines has the widest suite, whilst Emirates makes use of the space beside the grand main stairs to provide 2 showers in well appointed shower rooms (limit to 15 minutes use per flight, with timeslot bookable). Emirates and Singapore Airlines A380 suites have doors, and Qantas does not, but due to the angled seat direction Qantas suites are almost as private as if they had a door.
All of these suites have plenty of legroom in bed or reclined mode, however Qantas has an odd arrangement whereby seats face forward for take-off and landing and this has minimal legroom. The Qantas (and I think Emirates too) seat can convert to a bed with you sitting in it, whereas with Singapore Airlines you need to get out for a minute while cabin crew converts it for you.
The tables are good in all three - large so that a couple can eat together, and somewhat adjustable, although Singapore Airlines table has less flexibility than the others.
Of the little touches, I like the double blind system used by Qantas - lower one set to cut out glare while keeping the suite light and lower the second set to darken, I like the several air nozzles in the Emirates suites but the mini bar is a bit gimmicky for my taste.
All three suites have large screens to watch the in flight entertainment. The selection is the widest of the various offerings by each airline - Qantas has a special system not available on their other aircraft, and both Emirates and Singapore Airlines have their renowned comprehensive entertainment options. I've flown Qantas A380 twice and both times the IFE crashed in my seat (and other seats). 2 flights is a small sample so I could have been unlucky there.
Qantas and Emirates have a special touch screen controller to adjust the various suite functions (seat/bed positions, lights, etc) and double up as IFE controller. Singapore Airlines has the more traditional handset plus buttons in the suite wall.
On all three airlines, A380 first class has much the same soft product as other first class, and it is pretty good.
Singapore Airlines has a special menu for suite class (ie A380 first class) but really it is no different to first class menu for the same or equivalent route. All three airlines have great food and drink options, and the option to dine at your leisure (ie you pick the time to eat). One of my great pleasures of flying longhaul premium travel is the ability to take my time savouring a great wine and food menu. I think it is a mark of great crew to identify the pacing a passenger wishes to take and making sure they don't feel rushed or slowed down (in case of trying to get to sleep afterwards) unduly. I enjoyed a long slow meal with Singapore Airlines, for Emirates the flight is too short for maximum effect but there was some tailoring in the speed for each passenger, but with Qantas there was less flexibility offered in this regard - I felt rushed.
On the Sydney to Singapore flight Qantas has the degustation menu, which is a great way to sample many different foods with accompanying wine selections. Emirates had the least interesting food options, but for a 140 minute flight it was still very impressive (and far better than any on offer by any of the other 7 airlines flying the Tasman). Their longhaul menu was better still.
Cabin crew can make a world of difference to how a flight is enjoyed. Emirates and Singapore Airlines had great attentive staff who seemed to read minds when you wanted something. Qantas on the other hand continues to have a problem with consistent quality of cabin crew, and this was made worse with A380 by their decision to use staff on a newer contracting arrangement for this aircraft. Qantas appears to have accepted the negative feedback and since my flight has included other more experience crew in addition and is taking steps to improve quality all round.
How can you experience A380 suites for low cost?
Emirates flies A380 between Auckland and Sydney, and first class fares are relatively low (a little over US$1000 return). For longhaul look for fares from certain cheap originating Asian countries to Toronto. Otherwise, Skywards miles are easily able to be used on A380 first redemptions.
Qantas first class fares are never cheap. Look for British Airways premium sales to Australia - often these include first class (as return or one-way in business and one-way in first), and thanks to the joint services agreement on the kangaroo route these are bookable on the BA codeshare on the Qantas A380 flight as well. Otherwise, mileage redemptions are possible although hard to get unless using Qantas Frequent Flyer points (since QFF redemptions are opened at roughly 355 days before departure often prime awards are sold out by the time AAdvantage redemptions open at 330 days before departure).
Singapore Airlines blocks awards on A380 suites. You can get lucky, as I did, by booking an award on a flight operated by 747 before it is switched to A380. However, the easiest and surest way (for now) is to book first class between Singapore and Hong Kong and pick the A380 flight. Eventually Singapore Airlines must open up A380 suites to awards, but it has been over 2 years already with this policy.
I enjoyed the first class A380 suites experience on all three airlines. I certainly want to try Emirates on a longer flight. Qantas was the most different and also the most disappointing. I hope my experiences were an aberration as they have the potential for a very good service. Singapore Airlines offered all that I imagined, and lived up to their high reputation and my expectations from many prior flights on other aircraft.
If you have any questions, feel free to ask by comment and I'll try to answer.