My path has so fr been the SR60 >> SR80 >> SR325i >> RS1. The RS1 adds a whole new dimension to the music by adding depth and soundstage. As you are a SR60 user, here is what I think you will get with the RS1.
1. When you are listening to the SR60, add more depth to the music. Imagine more instrument seperation and you can will experience beter layering with the instruments, i.e. the drums will be behind, the guitar will be forward etc.
2. A more rounded sound. Music will all be more rounded and more musical.
3 The Bass will be punchy with a lot of depth. You will need quite some burn in for the tight Grado Bass to kick in.
4. My fav - More decay delay. The RS1 is almost good for music like Pink Floyd which require some note decay delay to enjoy. I did not at all like Floyd with the SR60, but with the RS1, its much more enjoyable. The Senns. I feel will be ideal for this task.
Many more things the RS1 adds to the SR60. It also strips off the pure foot tapping fun of the SR60 because it is not so immediate. But after a while with the RS1, you will love this presentation and will settle for nothing less
Save up and go for the big fish. At $695 the RS1 is not worth it. If you get one for $550 and lesser, its worth it. Also eventually you will end up upgrading to the RS1, so just go for it when you can.