Kreitlers with a headwind fan provide more than enough resistance for anyone I've ever met. Please note that I have never met Chris Hoy, so no need to explain that the headwind fan may not cover his all out maximum sprint power. Hard intervals such as 30 second max as noted are difficult on rollers, but they're much easier if you have a free motion setup. Learning to ride hard on rollers will keep your bike riding sharper than spending the winter on a trainer imo.
As mentioned directly above, I use the Inside Ride / E-motion rollers. I do out-of-saddle efforts on them, as well as z5, z6 work. I tend not to do all-out sprint (8-12") efforts on them, but when I want to spice things up I will do very hard efforts. 700-800w is not inappropriate for them. One could probably do max (short) sprints...it's just that I happen not to work on that during the winter, not that I think the unit is not capable.
I notice that as good as the 1up trainer is, after many months of riding a trainer I lose some of the subtle motions required to control a bike. Takes a short while to re-learn this out on the ride, so not a huge deal. However, with the rollers I find there is no transition time...not even a minute.
Just some things to consider.
I still occasionally use the 1up for some very hard sessions on the TT bike (feel a little more comfortable redlined on the TT bike on the trainer vs rollers), and for race-day warm-ups.