I use Rennsteig and Proto extractors.
Rennsteig (owned by and also sold under the Knipex brand):
Proto:
Rennsteig works pretty well if you use the drill bit recommendations. For the steel composition, I think they erred on the soft side though. I've had mine the flutes on mine get chewed up a bit at times. I presume they went this route because nothing is worse than breaking an extractor in a bolt you are trying to remove.
One thing I like about Rennsteig, which saves them from otherwise being redundant, is that because they have a hex head on them, I can use them easily with my manual impact driver - which is pretty clever if I do say so myself.
That way I'm hammering the impact driver into the broken bolt at the same time I'm trying to turn it.
Proto - those extractors are like magic. That's all I would buy if I were doing it again. I don't know how they managed it, but the extractors are very hard and have a lot of "bite" - yet I've wailed on them pretty hard without an issue yet. They are excellent.
BTW, you could do the same manual impact driver trick with Proto, but you'd probably want a set of 8pt sockets - or maybe a tap socket. 12pt might work if you got a tight fit, but I'm not sure I would trust it as much.
For pliers, I recently bought the new Knipex Twin Grips:
Similar idea to your Vampliers. Like all Knipex pliers, the teeth on them seem pretty hard and robust. So far so good. I bought a pair of extractor pliers from Westward a couple years earlier - those aren't bad either and were much cheaper. The teeth have suffered a slight amount of damage from use, but nothing terrible, and the pliers aren't quite as long so there's a little less leverage. I hear the Vampliers are pretty good too.
