For me it was NOT OK!
After installing it, booting took much longer, I had severe flickering in Safari (Videos and Flash content), some resolution problems with the secondary display and worst of all, VLC wouldn't play any video. Took me some time to nail it down to the security update 2015-001, but after restoring a system backup with TM, everything was normal again. Tried installing the update manually and repaired permissions before and after (as suggested somewhere else, I don't believe in it), but same problem.
So now I'm without security update 2015-001 and I'm wondering how I can safely install it.
[GA-Z97X-UD3H, Core i3-4330, 16 GB RAM, integrated gfx only, Samsung SSD 840 EVO, SATA HDD]