APPLICABILITY  I've had mixed experiences with Drive Genius. A while ago I got it as part of a MacUpdate promo and had a disastrous experience trying to use the "DriveSlim" option--and that with only the last three options checked (no checks for large/duplicate files, just unused optimizations, non-Intel binaries, and cache/temp files). It basically froze/became unresponsive (although the purty *cough gimmicky* animations kept on going), while driving CPU usage through the roof. I had used a similar tool, Xslimmer, to remove PPC binaries/localizations in the past, and the interface was much more user-friendly, responsive, and a whole lot faster. To this day I will never again trust Drive Genius to accomplish this task, update or no. The DriveSlim function may well be fixed by now, but I will never find out.

In fact, I was just about ready to never touch Drive Genius 2 again, when yesterday I decided it was time for a defrag. The first time around I tried TechTool Pro 5, only to discover that, when it comes to defrag (what it calls "Volume Optimization"), it might as well be called "Torture Tool" for what it does to the system. 5 hours in, the CPUs and consequently the system fans were screaming, and it seemed to have barely made any progress. After researching online I discovered that multiple-day defrag sessions with this thing are common--what a joke. So I looked for an alternative. iDefrag seemed like the most-recommended way to go, but I didn't want to pony up more cash if I could just use a tool I already owned. Although I was aware of the defrag issues users had had with Drive Genius 2, they had supposedly been fixed with version 2.1.1, and as I was using version 2.2.1 (on my Snow Leopard machine) I decided to give it a shot. What a difference in comparison to TechTool Pro! The thing was done in 3 hours, with absolutely no fan noise. It freed up around 2.5 GB. Not bad.

In conclusion, Drive Genius 2 is definitely a mixed bag, if for no other reason than that its reputation has already been ruined, between the DriveSlimmer issue I experienced and the defrag, partition, and repair problems I have read about on the web. On top of that, they charged users for an upgrade that for the first time fixed the horrendous problems that should never have made it in in the first place--not exactly what one would call a show of good will from the developers.

I will say, however, that version 2.2.1 was able to defrag my Snow Leopard machine no problemo. So props for that. If they keep making solid releases maybe they can slowly--very slowly--win back some reputation. But it will be a long and painful journey after the dogfood they served us in the   
(Version 2.2.1)