You may have missed the whole 'real RMS wattage' saga that took place.
Basically, I think most owners of the RH450 thought it was more like a 600-700W amp compared to the other micros. In fact, according to one magazines tests, it is actually something in the 230W zone at 4 ohms...however, magazine tests that delve too deep can often start to take the point off real life situations.
TC use a clever system called Active Power Management (like a modified compression) to 'get the most' out of every watt there is. The amp will never, IMO, clip, like a Markbass amp can. You could push it to full whack, it will react like a tube act (eg the notes will 'sag' a little and you may get a little overdrive and more warmth). That is what the amps do best.
The 750 is again not 750W RMS, however TC have stated the power module is capable of it, (as is the 450 capable of 450). If you took the APM off (which you can't) the amp wouldnt have the character it has, but it would produce the wattage apparently.
So, what you actually get is an amp that sounds louder than most other micro amps, yet apparently doesn't push the same 'wattage' technically.
I can tell you that the RH450 and RH750 are incredibly loud, and I don't regret going with TC's equipment.