All I know about SSD is what my brother in law says... that it's just instant. Even linux has a normal level of latency every time it has to load a program or to load in the first place. The SSD experience is that you just click and it happens. I think that SSD would benefit linux as much as it benefits windows.
I tried my nautilus, and you can right-click-> open-in-new-tab just like in firefox or chrome. But mouses are cheap, you should steal one from work or buy one from the supermarket for $5 if your middle click doesn't work. my wife's mouse you have to push really hard to get it to click, which is annoying, but anyway, the tabbed file browsing is still useful without middle click.
How risky is it to install more than one variation of Linux on the same drive?
I'm going with "not risky at all". If you're clever enough to write down (or remember) which partitions are for which operating system, then it's really not a problem. When you install the linux you like, just tell it what partitions do what, it's not rocket science, even I can do it. You can create partitions with Gparted, that's great, or you can create them as part of the installation. No special instructions, just read what it says on the screen.
One thing that's obviously hard is that if you already have a partition with data on it, and you want to retain it without killing it, and make it smaller, so that you can create a separate parition in blank space and put the OS on that blank space....... my VERY strong advice is to back that data the fuck up first. It's incredibly easy to kiss data goodbye. "Oh, you mean that I should have chosen SDA3 instead of SDA2?" too bad. data gone.
I would suggest that you use gparted to resize the partition without wiping the data (which is an inherently risky operation), then when it's finished put a new partition into the newly created free space. Record what it says is the relevant names of partitions on pen and paper.
Make a partition for the operating system (/root)
Make a partition for your linux files (/home)
Make a partition for your data (/saltystewsfiles). Mount /saltystewsfiles on the partition that has all your existing data (porn, right? it's porn more than likely. probably porn).
Step five is to not take my word for it because I'm drunk and probably wrong and you should verify for yourself that anything I've said is rational or sensible (which is the final brutal lesson of making the switch to the Light side: personal responsibilty).