Dang, every single person i know who has an ICS MP5 has never had any problems and has shot very well, but every one I've talked to with an ICS M4 has complained about their reliablility.
That's probably why I don't own any, too many conflicting opinions concerning their guns...
Concerning CA vs. TM, I think CA's a better buy if you dont want to do any serious projects with your gun since they come pretty much field ready out of the box (metal, sturdy, etc) TM's better if you want to make some sort of project out of the AEG, and I personally think that TM aegs have a much better hop up than CA. CA just hasn't quite figured out the magic TM AEG formula yet.