I have the X10 and love it
I have a 16GB SD card, so it holds a lot of pictures (or music if you want, but I don't use it for that). Aside from the issue with upgrading to OS 2.2, the only problem I initially had with this phone was the lack of battery life. At first it was hard to get through a normal day on one charge. I installed an app called Juice Defender though, and I noticed a huge, huge improvement in battery life. There are both free and paid versions of the app -- if you have the X10 I would highly recommend it. Phone is very snappy overall, browser is very quick. I have not had any problems with the keyboard.