I just went back to 10.1.4 also. I am on a mid 2011 iMac with 16 GB ram. Never had a problem with 10.1.4 but NOW with 10.2.1, it crashes all the time. Mostly doing titles (not the 3D titles but the regular titles I always use). I hope apple will get this resolved, but until then, I have clients who need their video and I cannot finish if it crashes every few minutes….