Well I have today spent a good 3 hours playing various kits in the music shop. I tried the Roland TD-11, TD-15, Yamaha DTX-540.
I can say that I was very happy with the sound from them all, and the variety of kits available.
As for the playing surface, I found the Roland mesh heads very comfortable. The Yamaha silicone pads were ok, but I feel that they might be tiring/jarring to play on after a few hours practice session, due to the hardness of the pad. The Roland toms are a little small, as previously mentioned, but that wasn't really a problem for me.
I favour the Roland kits, mainly because their software offers more useful features to me. For instance you can plug in a USB stick containing mp3 songs. You can also set up repeat sections in the song, adjust volume, and even slow it down to practice along with!! I found this to be a very, very useful feature, and spent quite a while practicing the intro to 'Bet you look good on the dance floor' with the tempo slowed to 90%. The Yamaha computer offers none of this functionality.
The only thing disappointing me with the Roland kit was the hi-hat. I found the pedal to be annoyingly unresponsive, and I had to practically take my foot off it to get the open hi-hat sound. I had to stamp it quite hard to get a closed hi-hat, and also the grading between closed and open didn't really seem that gradual. It would go from closed to open with only very slight movement in the pedal.
Now this may be configurable, but the shop assistant seemed to think it was ok, I didn't. Maybe the pedal was knackered due to overuse.
I did think the TD-15's VH-11 hi-hat unit was much better, and felt more natural to play, so I may consider an upgrade to that for my TD-11 kit.
So anyway, the only real downside to the TD-11 is the price. They appear to be very popular, so you get virtually no discount. Best they could do was knock the price down to £1100.
But IMO the Roland is superior to the Yamaha, so is worth the extra money.
I didn't even go near the TD-30KV, which was priced at a staggering £6500