I'm a relatively new commercial user of IDEA and just purchased an IDEA 7 license. I was pleasantly surprised to see SourceSafe integration included! Whilst this may have been a bit fiddly to setup initially, I'm pleased to say it's working like a dream now.
I did have one brief query: Can you configure IDEA to perform check-outs in the background? Our SourceSafe server is located at a remote site and is rather slow to access. The IDE just hangs whenever it's doing a checkout at the moment.