Yes it is good. My only gripe is that I don't like reading magazines on screen, and you don't get access to freebies (like cover CDs). Also it is difficult to read them in bed
They have the advantage that everything is hyper-linked within the mag so it is quick to move around and find things.
It is a while since I looked a Zinio, but IIRC you can also do text searches, which is good.
Out of curiosity can you redownload magazines if you damage a copy, and can you share them with others (one of the big advantages of the real thing)?
Personally I have a very bad experience with Adobe eBooks and am very wary now about buying any electronic books/mags that are encrypted.