Megasquirt is like any other open source type project, it has many "testers" and developers.
I took me about a year to get my megasquirt all working perfectly with all of the extras I wanted working on it.
Anyone can get a simple MSII install done within a few days, assuming you build it correctly.
The biggest problem I had was noise caused by my coil on plug, which is very hard to determine where the problem lies without a really good scope.
Finally got it running smooth, and its by far the most fun project i've tackled yet.
If you want something easy, or don't want to make custom parts, stick with a distributor.
I'm glad there is a huge userbase of megasquirt or I would have never figured out all my problems.
msextra.com has tons of help, as well as msefi.com
Also, getting rid of the maf was awesome, map+tps is by far more responsive and also more efficient in my car.