General advice:
- Don't buy new problems that you don't have with your current frame. For example, if your current frame doesn't have a slipping seatpost but your new one does. I did this when I went from a Tiemeyer to a 1st generation TK1 (the seatpost is now on its 3 iteration and much improved now)
- Understand that the point of diminishing returns is very near. A world class frame that you'd see in the olympics doesn't make any rider noticably faster. Maybe at the speeds at which they ride they save fractions of a second. But, to pay $10,000 to maybe save 0.1" on a flying 200 may not be worth it for normal folk. (BTW, most of them don't pay for their frames anyway.)
- Fit trumps everything. I was faster on a properly fitting aluminum Tiemeyer than my 3cm too small LOOK 496.
- A Bad Ass frame will make you feel faster and be a lot of fun. Not to mention that it may intimidate some opponents (human nature is human nature).
- 50.1 seems to be hitting the sweet spot that Tiemeyer left open...provided that you can get a frame that fits you. That's the only difference, Mr. Tiemeyer offered off-the-rack sizes as well as custom options.