Well, as for the last question, that's definitely true in the sense that there are some cheap-o snowshoes out there that might work okay for mucking around in flat mid-westerny snow, but don't do well at all in any kind of terrain and are generally flimsy. And there is nothing worse than breaking a snowshoe part way through a trip and having to post-hole all the way home. You won't go wrong with any of the pairs they sell at REI (for example) though.
The two main types that are popular these days are the aluminum frame ones (made by Atlas and others) and the all plastic ones made by MSR. In my experiance (and I think this is the prevailing wisdom as well), the aluminum-frame kind give better floatation and are better for general conditions, whereas the MSR ones are better on steep hills and ice since they are more flexible and have much more aggressive cleats. Some people think they seem flimsy because they're all plastic, but I've seen just as many aluminum shoes break.
I personally prefer the MSR ones for trails actually in the mountains. Cascade snow is really wet and on the cold sunny days you're really going to want to be out, the snow usually has an icy rind on the top, which means flotation isn't much of an issue, but traction is.
The aluminum-frame ones do okay in those kinds of conditions, and will do better in walk-in-the-woods type trips in valleys or on roads where there's deeper, fluffier snow, so they're probably the more versitile choice. You can also get "tails" for the MSR's that give you a little bit better floatation. The degree to which floatation is an issue also depends on your weight-- I've been on trips where I was going in every other step in my MSR's but one of my dainty companions was getting by just fine with a pair of yak-traxs.
My advice would be to try out both kinds before you commit to buying your own. Another issue is that the bindings are different from brand to brand and if you end up not liking a particular binding style, that can make you pretty miserable (a lot of people don't like the glorified rubber band bindings on the MSR ones, for example).
(Disclaimer: Since I've been using my MSR's exclusively for about 5 years now, I've been out of the market for a while so there may be developments I'm not aware of.)