I’ve done quite a few Coursera ones, probably started over 10 and finished 4 successfully.
The courses themselves are a bit hit and miss – of the 6 or so I haven’t finished, mostly it’s been due to the course itself, rather than personal failings – for example I started one statistics course but couldn’t handle the “children’s TV” style voice of the lecturer, quite a few courses aren’t quite what you expect (not necessarily the fault of the course), and more than one has been poorly prepared.
You do need to set aside a fair amount of time, Coursera at least tries to give you an idea of how many hours per week you’ll need, but if you find the material challenging (or they’ve simply got it wrong) you can easily find yourself doing twice as much. This has led me to drop out at least once, too. If you want to make a success of it I’d recommend getting the videos / lectures done before Thursday, leaving a full weekend to do any project work. You really do need to take them seriously! You should also make use of the course discussion forums, a lot of the time other students are having the same problems.
