I have several different types, but prefer my two chrome metal ones the most. I love the look as well as the "heft" of the metal ones the most. I just got a new type called a "cock sling" by Tantus but yet to try it. I love to see them on bottoms that I'm fucking face to face, especially the cockring/ballstrap combo types.
Word of advice, if you're going to try out a metal one, start out larger than you might think you'll need. Nothing like trying one on that's a bit too small, then getting a full erection from the sight and feel of it on you, and not being able to get it back off for a long time. This happened to me the first time I tried a metal one on at a porn shop when I was about 22y/o, and ended up having to j/o in the dressing room so my cock would deflate. :-)