See here's my feelings. Keep in mind I have an SR60, not 225.
I listened to the RS1i's and loved their bass and highs, which extended lower and with more force for bass and were slightly better (more sparkly) in the high frequency area. I can improve the bass performance (slam, quantity) by sacrificing a tiny bit of the lower midrange, resulting in a "muddiness". I however can't do anything further than I have to extend the highs, the flats are just as open as the bowls. The only thing that would change the highs would be to add comfies, but that would tone down the highs.
For me, these are fun headphones, not analytical ones. The extra oompf the flats gives the bass makes these infinitely more fun for rock music in my mind. This trade off for a tiny bit of lower mid range. If I want a more pure mid range, I'll go to my Fostexes. The bowls just have never done it for me. I know I am in a super minority here, but they don't sound that much different, minus the lacking bass, than the flats. Plus they are just uncomfortable to me. Again though, to each his own.
Once I get more happy with my source/amp, I will definitely go up stream headphone-wise. Especially now that I have heard the HF-1, RS-1 (and LCD-2 for that matter). I was tempted to buy the Rev 2.5 Magnums recently for sale, but decided to hold back.