I've got some experience using haml (+sass) on rails projects. I recently started using them with blueprintcss - the only thing I did was transform blueprint.css into a sass file, and started coding from there. I even have a rails generator that includes all this by default.
It seems that Compass does what I do, and other things. I'm trying to understand what those other things are - but the documentation/tutorials weren't very clear.
These are my conclusions:
Compass comes with built-in sass mixins that implement common CSS idioms, such as links with icons or horizontal lists. My solution doesn't provide anything like that. (1 point for Compass).
Compass has several command-line options: you can create a rails project, but you can also "install" it on an existing rails project. A rails generator could be personalized to do the same thing, I guess. (Tie).
Compass has two modes of working with blueprint: "basic" and "semantic" usage. I'm not clear about the differences between those. With my rails generator I only have one mode, but it seems enough. (Tie)
Apparently, Compass is prepared to use other frameworks, besides blueprint (e.g. YUI). I could not find much documentation about this, and I'm not interested on it anyway - blueprint is ok for me (Tie).
Compass' learning curve seems a bit stiff and the documentation seems sparse. Learning could be a bit difficult. On the other hand, I know the ins and outs of my own system and can use it right away. (1 point for my system).
With this analysis, I'm hesitant to give Compass a try.
Is my analysis correct? Are Am I missing any key points, or have I evaluated any of these points wrongly?
