Not speaking as an MR8 user,...
but my gearhead insticts say no. The MR8 is not a good choice of recorder for this purpose.
A better solution, by far, is
the MR8hd. Especially if you're basically happy with the MR8's fundamental layout and design, the MR8hd bring it to a whole new level. The MR8hd could record an hour's performance in 4-track simultaneous format, without so much as blinking an eye.
Not only (IMO) would recording in 4-tracks simultaneously on the MR8hd offer better production value over the 2-track recording you'd get with the MR8,... but if you're eyeing the MR8 and a 1Gb CF card also, you're already in the price range of the MR8hd.
The MR8hd gives you a lot more capability over the MR8 standard. I'd not envision the MR8 as a good recorder for recording gigs and performances, but I think the MR8hd would do quite well.
There are lots of other recorders I like, but based on your question, the MR8hd is my recommendation.
