Nowadays multieffects pad have pretty good distortion. I would stay away from Zoom if you think of recording music on computer since all the ones I have tried are really really noisy. Even with the built-in noise gate that usually only kills you sustain and leaves the noise lol
Anyway I never had a good zoom pad for recording.
I've heard very good rewiews about GT6 and RP200. I've heard recording done with RP200 and they sounded great.
I personnaly have a Yamaha DG-Stomp that I would never trade for anything. It's a discountinued model but it's just great. Yamaha has a new magic stomp or something, didn't get good reviews from the folks I know.
And one more thing, get one that has a built-in pre-amp ... gonna save you a lot of headaches if you wanna record on PC.
Hope this helps.