The Metalzone is allegedly usable, if you bung an EQ after it to let you shape the sound better. I can't really comment, not having used one myself, but EQ is always good.

As for multiFX, I'd strongly point you towards the Boss GT series. They sound good, they have a decent interface, they're getting good reports from people using them and they're very well built. I'd suggest a secondhand GT-3 (try ebay?) or a new GT-6. The GT-6 has some advantages; better amp models, more FX, knobs on the front panel for quick & dirty fiddling...

Don't buy anything that's in a plastic case. It clearly wasn't made for serious use.