Simon, this is why live distros exist. I have no idea what hardware you're using, but it sounds like you may be using off the shelf systems? Of course the laptop is. But if you would run some of these distros live you would be able to get an idea of how they're going to interact with your system without making any permanent changes.
There is documentation out there, but you do need a bit of basic understanding of systems. So far as the unity desktop, that's just a personal preference - if you don't like it you can always use (for example) ubuntu 10.04, which had a very nice version of gnome 2. I'm afraid ANY "new" distro you use, however, is going to require some relearning so far as the desktop goes because gnome has moved to gnome 3. I'm not sure which is more hated - gnome 3 or unity - but it seems to be shaking out a bit. I personally love unity, I was using a desktop similar to that for more than a year before this version finally was usable enough to convince me to switch to "ootb" unity. There are still a couple of bugs, but it's evolving quickly. I've used and supported a variety of systems and I still prefer ubuntu.
There's a wide variety of distros out there but they all use the same underlying code. Ubuntu funds development of some things, just like Novell funds development of some things and IBM as well. This is why there's diversity out there - anyone is free to evolve it as they like. This prevents the monoculture you have with OS X and Windows and makes the platform more robust. Complaining about the diversity of linux makes about as much sense as complaining about the variety of automobiles one can buy; if you don't like choice, you can always choose a platform like Apple where all your choices are made for you, and you can always ride the bus.
And yeah, the ubuntu user forum can be a bad experience. But I recall when I was starting out and I can honestly say the Mandrake and Suse forums were not any better. Support forums tend to attract two kinds of people: those who are complete noobs and need answers NOW, and those who believe they know all there is to know but have no life so they hang about in the forum. Those who know what they're doing have no need to be there, they're too busy actually doing it. I find the best avenue for answers is google.