I spent several months looking into different digital units and bought the BR-1180 CD 3 weeks ago. I previously used a Fostex X-55 4-track, so I'm kind of in hog heaven. Despite a poorly written manual, which seems to be par for Boss/Roland, the unit is incredibly easy to use. Using the rhythm track takes some work at getting right, but once you do, it's great. Initially folks were reporting problems of running out of recording time sooner than anticpiated, but it seems that was an omission in the manual and once foks learned to optimize their recordings, the problems seemed to cease. There is a user's group on Yahoo which has about 120 users and only one has had a unit that had to be returned.
There are also some updating issues for users who don't have the ablility to hook up to their computer, but BOSS says they're going to take care of that. There has already been one update released.
The guitar, vocal, microphone and speaker effects are amazing and provide just about any sound one could possibly want, plus you can adjust them to your own preference and save them.
I don't know that much about the Korg unit, except that the effects I heard on a demo unit don't hold a candle to the 1180. Having used a 4-track for almost 7 years, I'm really spoiled by this unit and find myself doing a lot more work with it. The whole recording process is much easier and more pleasurable for a non-techie songwriter like myself. Good luck with whatever you decide.
The link for the 1180 Users Group at Yahoo is in a previous post in this category, which you should be able to access using the search function.