I'd agree with Oaklands, really no difference to speak of. If they've been castrated you shouldn't get taint. Gilts can sometimes be a bit of a pain depending on how early they start coming into season - this is when they're likely to break out, going looking for some lovin'
and they tend to suffer piggy PMT (I think) and be a bit noisier than boars. The one obvious advantage with castrated boars is when the time comes for slaughter you're less likely to think "well, we could just keep them and let them have a litter" and chicken out of sending them
cos we all have those thoughts now and again
HTH
Karen x