I adore frames. I feel like they give you a lot better, more consistent tension overall. That said, bad frames can be just as difficult and poor as some hoops, so it pays to do your homework.
Also, most frames require more setup than a hoop, although if you're lucky the setup only really is necessary once.
I prefer the Millennium Frame from Needle Needs in the UK, but I know plenty of people can't afford them- either in the time it takes to receive or the actual cost. I know a lot of people use QSnaps, but I never liked them.
Scroll frames are generally good, but require patience to setup. They require extra work to get good tension in all four directions, but you can work with them without the lacing if it suits you. There is also slate frames, which I'd love to own, but haven't bothered with since getting my Millenniums.
This is a pretty good overview, and she has a lot of in depth looks on various frames on her site-
http://www.needlenthread.com/2006/06/em ... frame.html
In general, really watch the quality of the wood. Bad wood frames abound, and I notice a difference in my stitches when it comes off poor wood. With frames it's more important than hoops as the tension can cause poor wood frames to warp or weaken and eventually snap.
