I have been reading through posts and hear there is an issure with this. It suggests not to do this in the book, but some posts are saying this only refers to on the same side, as opposed to using, say, mic on the L and guitar on the R. Can anyone clear this up for me, I cant find out myself since I am currently using garageband which doest allow multitracking. I want to get Logic later and dont want this unit if I wont be able to do this later.

Garageband 2 allows multitracking. Might be worth upgrading?

As for the US-122, yes, I seem to recall something about not using the mic and line inputs at the same time. It's not a unit designed for intensive multitracking - it's more for the home studio, one-track-at-a-time kinda guy.

If that's not you, and if you genuinely have more ambitious recording sessions planned, maybe you need to double what you spent and get, say, the PreSonus FireBox or something similar.

If you want to get Logic later, the US-122 will work with it, by the way. But you'll still have the I/O problem you mention.

The US-122 has mic & line/instrument inputs on the left and right channels. You can use a mic on one channel and an instrument on the other, but you're 'not supposed to' use the 2 inputs for a given channel simultaneously.

IOW, there's 2 plugs per channel, you're only supposed to use one at a time. In practice, you can use both, but if you have a mic & instrument both plugged into, say, channel one, you won't be able to adjust their relative volume using the faders on the 122.

Thanks for all the advice, but I gave up on it and bought a firebox, it seems to fit the bill a lot better.