Slatkin's CD version was the first Mahler 2 on CD that I purchased, I think around 1985. There was very little Mahler on CD in those days, so I had to have it as #2 is my favorite, and I hung onto the recording for quite awhile. IMO, it was pretty impressive "in its day".
As more Mahler became available, I turned to the recording less and less. I agree with Barry that the first movement is not really exciting in the Slatkin recording (many M 2s don't have exciting first movements, IMO), but it is certainly a fine recording and performance over all. I think I sold mine when I got Blomstedt's recording with the SFSO, which I felt had a thrilling first movement.
I don't have Slatkin's SACD version, but there are so many extremely well recorded 2nds out there now, I doubt it has any better sonics than the best out there.