I did own both Signatures for some time, sold the Sig DJ and kept the Sig PRO. A few weeks ago I came across a demo station of the new Bose QC 25. I will not recommend them over the Ultrasones sound wise, but comfort wise, they are light years ahead. I am wearing glasses too like you. It is all about the pads my friend, this is where the comfort lies. Those Bose pads, you can wear forever, you forget that you have headphones on...I do not own the new Performance series, but I guess the comfort improved a lot on these.
Interesting. I can't see myself selling my SDJs, sound is too perfect :) But after more reading it definitely looks like the new Perf series have improved comfort - and the 880s come with a set of velour pads too which would be great especially in warmer weather. Very tempted..