My Surface 2 arrived today hooray! It's funny how spoiled you get, it felt like an eternity waiting for it to show up but compared to the competition PC World were slow to deliver (ordered on Saturday).
Haven't had it that long but I'm positive about the changes, the back feels more like plastic but it's also less fingerprint prone, the volume switch has less play than my original Surface and the power button is firmer and more prominent (I use that button a lot so it's a nice little difference), maybe that will change after it's a year old but it seems like an improvement all round.
The screen appears to be a big improvement, the only downside I've noticed is the back lighting has a bit more bleed (the original also has this but it's very hard to notice) and otherwise the extra resolution, improved colours, it seems to be a lot brighter too and the lack of the grid pattern underneath the display (I assume it was the digitizer on the original Surface) but it can be hard to see without sunlight so not completely certain about that last point.
The type keyboard is very nice, really weird feel when folded back and handheld but I mainly upgraded because despite all the performance improvements the original Surface still isn't great if you're jumping back and forth in IE, animation effects (menus etc) popping up on YouTube and so on. Fortunately the Surface 2 works fairly well here, it's still not as snappy as a desktop but it's responsive enough I don't feel I'm waiting on the machine and considering how much I use the Surface that matters to me.
The speakers are worse though, less bass and considering the original speakers weren't that great it's a shame Microsoft appear not to have bothered much in this area. Some bits of the finish look worse, the top is actually about the same as the original but on the 2 you can see it from the front so it looks worse.