Abantecart is very good for the most part. I say, it is important to start with learning it.
Most parts are intuitive, but if you need to get into more complex set up, it might get tricky.
I was thinking of a bad side, and not able to come up with much. Possibly, the marketplace with extensions is not yet very big on variety. I guess this is a matter of time as I see extensions add up quickly.
