I picked up the TB last Monday coming from a Droid, Incredible, Droid X (favorite). The TB is a battery hog for me and I'm not even in a 4G area (coming to my area in next month). I know a ton of people dog Blur, but there are hit and misses in both UI's IMHO. The reception was actually as good if not better for me in an area where HTC in the past has failed MISERABLY in reception for me.
The X with all the dev's and themers and forum support is far and away the phone to have for modifications and ROM's. TB has root and luckily a dev put together an automated ADB process, but boy is it a pain. I assume that with time, it will get some love, but it won't be within your exchange date(s).
The other thing that drives me nuts with the HTC Sense is the inability for phone and other apps to be in landscape mode while driving and while not. I can't stand the car dock app's (phone will work in landscape mode while in car home app), but being a road warrior, this was/is an issue for me. Also, the actual car dock from Verizon is cheap. Not a fan.
As for the SD card, I purchased a 32 sd card (Sandisk) a while ago so that was not an issue for me if I decide to roll with the X2. There are features about both phones that are a plus for me and also a minus. That's the thing that really sucks for some is that there never seems to be the makeup for that "perfect" phone.
Somehow, this turned in to a rant. Sorry about that.