I find that saber grind chops a bit easier, due to extra weight behind the swing, but full flat will often baton easier, because it doesn't have that sharp angular transition which can dig into the wood and slow the blade down.
For chopping, a full flat can potentially bite deeper, but when you're chopping with good form, alternating side to side to cut out a wedge, the small difference in biting depth is less important than having the momentum to send chips flying.
Now, if you have a HUGE difference in bite depth, like, say, a machete versus a dogfather, then the difference will probably be more noticeable. That's why my very thin CS LTC kukri (still a saber grind, but a much thinner blade) or Horn Dog's machete's chop so much better than many "choppers". Those very thin blades can bite really deep, and remove a lot of wood quickly.
And adding even more confusion to the battle is the issue of fatigue, a lighter chopper or machete is going to wear you out less than a heavier one, although the weight of the heavier one will do some work for you.
It's a balancing act of a bunch of different stuff that will vary wildly with preferences and personal style, so your only solution is to buy a whole bunch of both, and decide which you like best <img src="/ubbthreads/images/graemlins/thumbup.gif" alt="" />
