well it depends on if you are going to be showing. rubber reins don't look great in the hunter ring but if they are just for schooling they should be fine. i have found that i get blisters from them without gloves but some people don't.
Edgewood makes awesome rubber reins (and I typically don't like rubber). D'yon also makes nice ones. My pet peeve is when clients get cheap ones and they get sticky or even start to melt in the heat and I have to ride in them, so I'd get quality ones.
Obviously, rubber reins have a better grip. I like them myself but some people feel that they are a bit heavy. They also tear a bit easier if the rubber isn't thick. So when I but new rubber reins, I like to make sure its good quality. Overall I like them.
I really only ever ride in rubber reins and I keep my grips almost always as long as I'm paying attention (lol). My one problem is that if you have a heavy puller on the other end they show wear and tear faster than leather.