Here’s a short visualisation of how I perceive various revision control systems, given in the order of my being exposed to each of them throughout all those years.
BitKeeper
Many winters ago, it was the first RCS I used and I remember it was pretty powerful yet somewhat clumsy to steer and handle not to mention the thick armour that wouldn’t let me peek inside and have a look at its source code. I hear it’s still being sold to customers around the world who don’t mind to trade a little bit of the manoeuvrability in exchange for its main gun’s fire-power.
CVS
A funny-looking though not really forgiving system that would bring a lot of projects home. The crucial point was its low price (opensource) yet the lack of features (like no real ‘reverse gear’, one couldn’t easily delete empty directories) meant I was looking for something else pretty soon.
Subversion (svn)
Now, I spent a couple of years working with svn for various corporate clients and it’s clear that’s what the prevailing majority of them can easily understand. It’s a centrally-managed system with no push and pull steps like in those fancy modern distributed ones and usually does its job sufficiently well. The feature most important for all the selfish ‘enterprise’ clients is that it has a built-in lock command with the power to break the locks if need be.
Bazaar (bzr)
A very versatile modern system whose only issue was the maker’s marketing department who in the system’s early days wasn’t able to stop warning people that features were first and the speed advancements would come later so in the end pretty much everyone still thinks the system’s slow. Well, it isn’t. It’s called being ‘fast enough’ my friend. Oh, and the maker’s move to hire a couple of experienced user interface designers means the system’s a pure pleasure to use with no surprising commands required for everyday usage.
Mercurial (hg)
Another system that’s good all-around, fast, fuel efficient and very comfortable to drive. Doesn’t have as many fans as it deserves to because it’s not called Volkswagen Golf even though 99% of the features are precisely the same.
Git
So now it’s git. A prime example of why space rocket engineers shouldn’t really design end user-facing technologies. It’s fast and that’s all one can say. There’s no hood so all of the gory details are left exposed and you’re supposed to deal with it (like it’s natural that one needs to check out two consecutive dashes when there’s a need to revert something). Just notice the number of times the words ‘unusual’, ‘surprising’, ‘unexpected’ get mentioned in books on git. Really, the only thing that makes git usable is GitHub, which indeed is a very good service, like git done correctly only in the browser.
I guess you can easily tell who my heart is with, eh? 
@fourthrealm
