On the positive side: overall, I'm pleased with it. Conceptually, it's excellent, being able to customize a sidebar assistant, very useful. While I enjoyed SysMetrix, you were limited by the specific skin to what tools you had, and if you found a perfect set of tools but in a hideous color, well, you better learn how to work on skins. GD may look more bland, but knowing you have exactly what you need and nothing you don't is a huge plus. Making it possible for 3rd parties to write new modules for it was also smart; like Firefox extensions, it opened it up to a vast online community.
This has it's downside, though. Opening it like that means little quality control, since every Tom, Dick, and Harry can try to write a module. For instance, one module I added allows for control of WinAmp, which I missed having. Problem is, it has no pause button or volume control, and doesn't load the playlist like it's description and screenshot claims it does. Forum crawling revealed others have this problem too, so hopefully the author will fix soon; in the meantime, it's better than nothing. Another example, I found a module that monitors hard drive fragmentation. Nifty, I thought, I know I need to defrag, let's see how bad it is. It claimed my Main drive was hideously bad, so after spending a couple days just burning files (I needed to do it, anyway), I got around to defragging. The system's analysis showed a vast improvement, but the module showed almost none. Turns out that the module is a freeware cripple of a larger paid version, and this freeware one will only analyse up to 80GB. Seeing as how my drive is twice that, it wasn't going to give me an accurate reading. It's been dumped, obviously. Last issue: found a module that is just a clock, but which claims I need a newer version of GD. Google, however, doesn't think there IS a newer version. Interesting. For all that there are lots of modules, I find that most of them are too specific for general use, but I suspect that as time passes, there'll be more created.
All these problems, though, are not a problem with GD itself. I've only had one issue with the actual program, which wasn't so much something working wrong as much as it was working right: GD does try to stay on top, if open. normally, this is what should be happening, but if I fire up, say Unreal Tournament, which goes full screen, or Photoshop, which expands to fill the screen, the programs fight for dominance. Photoshop just fills the rest of the screen, which gives me less space to work with than normal; UT fires up in a window instead of fullscreen, and has to be reset. Both of these are easily remedied by switching GD to show "none" before launching, and after shutting down said program, clicking it back to "sidebar". Since it does this quickly and easily with no loss of info or position, I don't see it as a hardship.
In the end? I'm pretty satisfied. Now, if I could just stop playing this song...I'm pretty sure it's been on repeat for almost an hour now...