As Chip (the other one) said, Metz makes really good gear. The 45 CT-4 is pretty powerful and recharges quickly with the accompanying battery pack. It's great where you need portable (camera or bracket-mounted) light. As far as using one in the studio, it's a hassle to mount and modify (use umbrellas, softboxes, etc). It's output is equivalent to something around a 200-250 w/s strobe, but it doesn't recycle nearly as fast as a monolight or pack/head and you (of course) don't get a modelling light. If you watch the recycle times, it makes a nice background light.
I guess the bottom line comes down to price. Brand new with a TTL module, the latest incarnation of that flash runs nearly $500. Only you know what you're willing to spend on a used one. If you are looking for on-camera flash, you won't do much better. But if you're looking primarily for something to use in the studio, You'll get much more for your money by purchasing a monolight or pack/head kit.