We use a system built on sakai at my university. While it isn't horrible, it isn't brilliant either.

In the CS department we have a command-line utility for submitting homework and grades, and the classes just have a simple website. Everybody likes that system more than the one based on sakai, which should give you a good idea of how much functionality sakai brings.

Additionally, everybody is now using a system called piazza[1] as an online forum for the class instead of using the one provided by sakai. I rather like it and it has met considerable success in most of the classes that deployed it. Of course, some of my professors are very enthusiastic about this system; one of them even has a testimonial on piazza's main page.

[1]: http://www.piazza.com

I found Sakai, at least in the "T-Square" rebranding used at Georgia Tech, pretty annoying also (as of a few years ago), but at least it isn't sucking millions of dollars from their budget. At the time (possibly now fixed?) it had a very strong single-session assumption that would cause weird things to happen if you did obvious tabbed-browsing things like opening multiple users' assignments in new tabs. The "solution" was big red warnings at the top of every page about how you shouldn't do that.