A ported 15" vs a sealed 10" in that size room I'd lean towards a larger ported sub rather than a smaller sealed sub (or at least two of the smaller sealed subs).
This is one of the few Klipsch subs it seems worth having by most accounts. Got a
decent review/measurement from Brent Butterworth.
Velodyne has a good rep for some of their subs, but has largely abandoned progress in audio (for more lucrative fields) some time ago now and when I looked recently had no support for stuff at all at the moment as they've just changed ownership hands, and I suspect that won't change the support for older gear (probably more important for their servo subs, this doesn't appear to be one).
I wouldn't put too much into comparing wattage ratings, without the sensitivity/impedance/eq details doesn't mean a lot....
Do you need the sub to have dsp? What will you use it with in the way of avr/pre-pro?