I've tried two vaporizers: the BC Vaporizer and the Aromazap. The BC was the type where you put the weed in a bowl that heats up and has glass bowl on top. It cost $50 and was a waste of money It kinda worked but took quite a bit of bud to get high. Don't bother with this type no matter how attractive the price is. You'll end up spending more in the long run with the extra bud you'll buy

The Aromazap, on the other hand, is awesome. This is the convection type of vaporizer that draws hot air through the bud as you inhale. I've found that I can get really, really high with just a little bit of bud. This one only cost $100 plus and is worth it considering how little bud it takes. The only problem is that it takes 30-45min to heat up. It doesn't get too hot, however, so you can leave it on a long time. I've actually put mine on one of those cheap timers so that it's hot pretty much whenever I am home and awake.

I don't know how much better some of the really pricey vapes can be. The only thing I can think of is that they heat up faster.