the only problem with Magento is the fact it is overengeneered! And once you decide to work on it yourself, you will find out no documentation, no community support, etc.
But if you like to model everything - you will like digging in it's code. Just do not forget primary reason you installed magento - sell something to client ))))
I'm with you on the community thing... I mentioned how slow and bloated Magento is on their forums and was told to go and buy a faster server.
Yea.. That is the solution sometimes.. but on a fresh install it's total garbage. I understand what they are trying to do, and it's great, but the learning curve is stupid retarded in my opinion. And without a coupon system in the free version it's worthless. But that's besides the point.