Yes, it's easy to get overwhelmed with so many choices. On the other hand, the worst vaporizer is better than smoking, so get one soon, even if it's not the one you're gonna marry (in a matter of speaking).

Like 420barista says, a lot depends on how you will use it. You have portable vaporizers, and you have non-portable ones. By non-portable, it's not that they weigh three tons; it's just that they need a power outlet. The portable ones are usually but not always powered by butane. Also, will you use it all the time, or will you use it three times a week? The more you use it, the less you can tolerate the little things that bug you.

If you've been smoking for a long time, I would recommend a Vapor Genie. I've had one for 3 months, and I use it all day long, every day. You can google for all the info on it, and there are reviews about it here as well. I think it's a good way to switch to vaporizing. However, I have decided to upgrade. I got the Vapor Genie while still skeptical about vaporizing; now that I'm convinced, I have ordered a Da Buddha vaporizer (DBV).

Here is why I ordered the DBV and not...

...the Volcano. Price wasn't the issue since I know it will pay for itself sooner or later, but it only blows bags, apparently, and you can't use a whip (the tube to suck vapor from).

...the Silver Surver. Here price was the issue. DBV and SSV are made by the same company, and the SSV has some extra features that I don't need.

...the Vapor Bros. Some people have criticized the air path (goes over the wiring, apparently), but my deal breaker was the downward angle at which the whip goes into the unit. The angle makes the herb fall into the heating unit itself, and some people say that's not a problem, but I decided not to risk it. The DBV's whip enters the unit horizontally. The other thing about the Vapor Bros is that the screen in the whip looks tricky to replace. They have an improved whip, but I don't believe it comes standard.

...any unit with a digital readout. The display is just eye candy, and in most cases does not measure the temperature of the air that goes through the herb. It measures the temperature of the heating element or the air at some other point. The readout is not necessary as you will know where to set the knob as you get to know your vaporizer.

...any small, complex unit with lots of electronics and plastic parts. I prefer the simplest unit possible.

...any unit whose major feature is "hands free." Hands free means that you stick the whip into the vaporizer and it stays there. You then hold the mouthpiece end of the hose and take hits like you were smoking a hookah. So it frees up one hand, but after a few hits, you have to take the whip out to stir the herb up anyway, so I don't see much point to hands free.

Ok, so that was how I narrowed it down. Hope it helps!