Build/Reliability: Probably more reliable than my IBM-era thinkpads. Excellent build quality, NVME, good battery life, slim aluminum frame, and one of the better notebook displays with retina. Trackpad is the best in the industry period, no one has anything as good or responsive.
Support: Very big support network. I can walk into a store and get a loaner, fix, or a brand new machine. If you don't have your own IT department this is a huge value to your startup/small business.
OS: If you want to develop for iOS there really isn't an option, so that's not a fair comparison. However, Apple supports practically every professional level software suites (Adobe, FCP, etc). OS X is also certified Unix with a polished ui and has pretty good compatibility with most of Linux/GNU with homebrew.