2.8Ghz 512Gb 13" RMBP, same new updated directly to Yosemite, no issues at all, everything is super smooth no complaints, running marginally smoother than my 2012 2.3Ghz 256Gb 15" RMBP (Intel GPU), equally SSD is faster on the 13" so far very impressed with the 13" Retina
Q-6
so pleased that i have find you owning a rMBP 13"
have ever installed any game on your device? have you ever encountered any problem due to Intek iris graphics?