Not according to a lot of people. Common criticisms are:
- "kiddy OS"
- "terrible for the enterprise"
- "cheap for a reason"
- "just a pretty GUI"
To take the enterprise criticism first: I agree. It's not made for the enterprise. Apple knew that most Windows/Linux sysadmins would never consider Apple servers, and with the demise of the Xserve they've made that clear. Apple would have to be insane to sell an enterprise server OS for £13.99 (plus ML). It is made for home and small business users that don't have a dedicated sysadmin who's on call 24/7, who don't run a high traffic website, who just want it to work with their Apple products.
"kiddy OS". OK. As I've said above, it's not for running the next YouTube. It's for a simple server. It still offers Terminal, if you want to get into the Unix side of things. And for most people, setting it up is very quick and easy. Explain how this is a bad thing?
"just a pretty GUI". Again, it's simple and easy to set up. And it's based on Unix.
To sum up, it's like Windows Home Server. This never got this criticism, and OS X Server is more reliable, and cheaper, than WHS. Call me an Apple fanboy if you will (God, I hate that term) but Server isn't that bad, and it works with not just my Apple products, but also my Nexus 7, Ubuntu and Windows PCs etc.
People who dislike OS X Server are welcome to make their argument in the comments.