I prefer pneumatics. They have a higher quality feel about them. I also think that they're more life like and rugged.
I dislike the way that you have to have loads of axles and gear to drive a LA, seems messy and is also inherently weak. A pneumatic cylinder will work under higher loads than a LA. LAs may well be more precise but I can't stand the gear slipping that you get sometimes when trying to operate them.
As for smoothness, there's nothing smooth about a hand cranked LA under load, in my experience. Very jerky.