No - I don't have any experience with those amps. I think all the ones you've mentioned are very good from everything I've read at headfi.
I didn't bight the bullet on the 701's because the Senn 600 with cardas cable is an amazing phone. I also have the Grado RS-1, AKG K1000, and feel that the Senn 600 is the most nuetral and accurate phone (although I love the musicality of the RS-1 and amazing sound of the K1000). I think the 701 would be too similar to the Senn 600 which I prefer over the Senn 650. So, I haven't had a desire to get it.
I didn't bight the bullet on the 701's because the Senn 600 with cardas cable is an amazing phone. I also have the Grado RS-1, AKG K1000, and feel that the Senn 600 is the most nuetral and accurate phone (although I love the musicality of the RS-1 and amazing sound of the K1000). I think the 701 would be too similar to the Senn 600 which I prefer over the Senn 650. So, I haven't had a desire to get it.