how much difference is there in ride between step and non step hull ?

In chop not much, stepped side by side much flatter in calm water less hop or porpoise, and about 10 mph faster. I know a few guys with both locally if you want to check either out bill.

I think closer to 15mph faster. Steps do fly level, trimming does not bring the bow up like a straight bottom. Seems like t/s slap waves more and you can feel they are much lighter. Another thing I noticed with mine is when you pull back the throttles it doesn't slow down it keeps going. My old boat felt like you hit the brakes when letting off. I wouldn't say one is better than the other, they're both top guns.

Is there a noticeable difference in fuel usage?

Yes because a t/s needs 500 efi's to do 80 and well you know how much a straight bottom takes lol

yea, I been on a 525 stepped 38 gun runs 84 all day long, to do that in a straight hull takes all of 800++ hp....

non step is better in the rough but slower than a ts

I've never noticed any real significant difference in 'ride', although you probably would feel it in handling racing it through a tight slalom course (which nobody would ever do). In the rough some might say the flat bottom might have an advantage, but since the TS runs flatter, the bow being down a little more seems to break the waves better and smooth out the ride IMO. The flat bottoms tend to ride with the nose higher and use less of the hull.

The stepped bottom is obviously more fuel efficient, desirable, and about 15% faster all things being equal. Since the TS's are newer, they are generally in better shape and come with nicer/more modern paint. Obviously they are also more money too, so it's probably not a fair direct comparison. With that said, I would absolutely choose the TS over the older flat bottom if given the choice.

Easy, T/S if you can afford it
Flat Bottom for everyone else!

T/S sounds like the way to go cat might be going miss the cabin of a v