I've migrated from the 6700 - 6800 and now the TP (I believe Sprint designates it as the 6850)
Just my 2 cents worth but there really is no comparison. Most of the people who have some reservations about the TP vs. the Mogul in fact haven't really tried the TP yet (they've just read about it). Again, it's really no comparison.
I'll just give one example:
Out of the box the Mogul needed to be tweaked almost immediately to get it working in a decent manner. Reflashing was almost a MUST. I can not even imagine using a stock Mogul.
Sprint and HTC must of did their homework with the TP. Although far from a perfect phone, it is usable right out of the box. Reflashing is still nice but it's not as necessary as it is with the Mogul. Believe it or not, some of the junkware is actually useful. The screen is so much sharper. And the possibilities for the accelerometer are endless.
And one final thing: I challenge anyone who has never used a TP before, NOT to say the word "cooooool" the first time they ever play Tweeter....
And if you are at the end of your contract and are looking to upgrade, this week's BB price of $199 is almost a no-brainer.