It really comes down to this: The SL8 is going to be more accurate, but to get it to the same level of ergonomics and functionality you're going to have to drop some additional coin on it - to the point where you might as well just get a Swiss Arms or ACR with a NR match barrel. Reliability is probably a toss-up between the two (possible edge to the SL8).
Since the OP has indicated budgetary considerations are a key factor, this really only leaves the MR1 - and contrary to popular belief, no one else really shares caramel's high opinion of it. The additional calibre options for the XCR-L (or the XCR-M) give it an edge in the multi-use roll. Truth be told, a factory NR ACR or Beretta ARX-160 would wipe the playing field - but since both are unobtanium...