The new 10.8.2 update is solid, and a good idea If you’re on Mountain lion.
But there are some problems with 10.7.5, particularly with Time Machine and Spotlight. I’d stick with 10.7.4 for now.
UPDATE! Apple issued a “supplemental update” for 10.7.5 today. Why they hate calling it 10.7.6 I don’t know, but Time Machine and Spotlight issues are mentioned in the notes. This may fix the problems people have been having.