A few years ago I built an ap on a pc engines alix board. Of course the choice of wireless card is going to be the deciding factor in performance as the alix's cpu and ram is higher than most wireless appliances. My performance was good but not as good as similar priced appliances. I am not using it atm because I'm using a skinny 4g modem. If I needed a wireless ap in the future I would buy an appliance over built due to cost, time, and performance. What you loose out on appliance ap is software and security upgrades. Also the coolest thing with building a router based on debian is you can install anything you want. But if you want to install proxy server, file server and virus scanners don't go for an embedded chip, get a proper pc with decent cpu and hard drive. And lastly I tested the original raspberry pi as an ap. Throughput was terrible. About 1mb per second file transfer speed using rsync, my understanding is that is due to everything running through its USB controller