After racing 2wd SC for the first 3 months of my rc racing life, I am now learning how to drive 2wd buggy.
IMO the buggy is easier to drive, in that the precision and nimbleness can make a small track feel wide open. However I also feel that the buggy is more difficult to drive fast... competitively fast.
2wd SC can be a little unpredictable at times, which can be great equalizer amongst a field of various experience, but can also be a source of frustration if one takes it too serious.
The buggy also seems more responsive to setup changes. A millimeter here or there and it can go from dialed to un-drive-able.
I was starting to get frustrated with my SC, but now the practice and tuning experience with my buggy has carried over to my SC. It is now running better than ever and I can't wait to race it again.
So my advice: buy a 2wd SC. drive it, race it... when start to get comfortable with the SC get a buggy.