It used to be that recurves were 'better' - the recurved limbs were able to transfer energy more efficiently to the arrow in(that's historically true, not just for the relatively modern sport of bow hunting).
With modern materials and the new reflex/deflex longbows, there's little if any difference between longbows and recurves of comparable quality.
The thing that always stands out as the big difference to me is the types of grips - recurves tend to have more contoured grips, whereas longbows tend to have more straight handles...and the way you grip a bow is key. Some people prefer the feel of longbows, some recurves. The best way to figure it out is to test shoot a bunch, if possible. Find one that feels good in the hand, pulls smooth and shoots straight...beyond that, I don't think the shape of the limbs matter...
...although I like the look of recurves better.