Any reason in particular? I would agree over the TX2, but the TM2T's are really nice. And extremely well reviewed. Mobletechreview gave the TM2 it's editors choice. The Thinkpad is clearly a better tablet, better screen and processor, but the TM2 is no slouch and has touch that is as good or better and pen that is everybit as good.
Of course, the price difference is massive. The X201t is over $1600 more than my TM2 when you upgrade the HD to 500GB and RAM to 8GB to match my Touchsmart, and I am getting better graphics options than the X201t with the Switchable ATI GPU.
For me, I opted for the HP since it was reviewed very well and it was much cheaper than the Thinkpad. So far, it seems like it was a good choice. My TX2 has been extremely reliable, and I have no reason to suspect that this machine will be any different.
http://www.mobiletechreview.com/notebooks/HP-TouchSmart-TM2.htm