We were all issued desktops and netbooks. The desktops are actually high quality and I've never really had a problem with them. The few instances where I had trouble was when I had to deal with all of the USNA network/security/updating software that was preloaded onto it by the IT department.
The netbooks, however, suck. They are extremely slow, are bogged down by almost any piece of software you try to run on it, and for some people (including me) won't even connect to the USNA wifi networks in the different academic buildings. The only thing they're really good for is viewing documents away from your desktop or watching movies, but we were all issued an 880 gigabyte hard-drive that makes the task much simpler, and a lot of mids just use their phones to check email/view or transfer documents.
I bought a macbook pro about a year before I reported on i-day, and I definitely don't regret it. Although I can't connect to the internet with it on academy grounds, I am able to at my sponsors' and other places, and it just runs much better than the issued netbook. If anything I prefer to do homework on it and then just convert the file format and transfer to my pc to print off, as not having internet access helps me concentrate more on getting my work done. It's a great machine.