I own the S1 and have used the S3. While I can't say on the S2 specifically the S3 did have many features my own did not. I'm guessing that the S2 is somewhere in between. I found both cameras easy to use and both take great shots.

If money is a problem I'd go with the S2 myself if you don't want to wait and save up for the DSLR.

Have a fun vacation.