To me, the sequence must be Rough-in Distance (distance from wall to centre of sewerage outlet > Budget > Design. No point going around sitting and choosing WCs only to find out that they are not suitable or out of budget. You must first measure the distance from the back wall to the centre of the sewerage outlet. Based on this dimension, maybe only 50% of the WCs in the shop may be suitable. I don't recall having to measure the size of the outlet or understand P/S trap. Most WCs, I understand, come with adjustable collars or convertors to meet the actual dimension. I have one with S trap and another is P converted to S trap. No difference to me visually or in usage. (P.s. P trap means outlet in the wall, S trap means outlet on the floor, which is more common). Next, your budget may put another 25% of the WCs out of reach. Finally, from the remaining 25%, choose a WC that meets your taste. I was intrigued by the suggestion to do a sit test for every WC. I have never done it, never seen anyone doing it. (Do we have to remove our pants?). Jokes aside, in my opinion, for comfort, the most important part is the toilet seat. A more solid seat is more comfortable to the bum. Something that feels like a piece of plastic about to break into two when you sit on it is no good. For those with bigger bums, or whose firing or bombing precision is not so good, a bigger bowl (and seat) will be more suitable. But usually more costly too. In my case, a visit to Japan changed my life forever. I fell in love with the Japanese toilet seat. It warms your seat (in winter), plays soothing music, sprays warm water to gently clean your bum, blows hot air to dry your bum etc. In Singapore, we do not need to go for the $10,000 and above model. We can settle for the basic model which sprays water to clean your bum. No need for power supply. There are now many models in the market, but the one I chose was from Toto. I feel it is better built. The price of the Toto Washlet is from $250.00 to $1,000.00 depending on size, features, soft closing, bidet function etc etc. For Toto, you can go visit the showroom at Bukit Timah, opposite KK Hospital and next to Sim Siang Choon, or any of the many shops at Balestier that sell too. But the shop I like best, and bought from, is Fullsun at 146 Jalan Besar. They have a full range of Toto WCs and toilet seats. The WCs also have water connection, so you can flush and see how the water goes down for each model. (No, I don't think you can poo here). Or you can try this website, which has video too: http://japaneselifestyle.seesaa.net/category/1714188-1.html I have been using my Toto WC and washlet for some time now. I don't think I will ever be home without it!