i remembered back when Logan was talking about routers and how "box store routers" are just very weak pc's with routing firmware in place. afterwards, he proceeds to mention ALIX and how convenient it is for making it into a router. i guess i have a few questions about ALIX.
It all depends on what you want to do. Hardware with custom firmware has so much more potential but requires a bit more work on the finer points. I'm actually messing with DDWRT on a Linksys wireless-n router and it has so many more features than the stock firmware.
Hardware wise building your own router will probably cost more, however you have the ability to say put two wireless-AC dual band wi-fi cards and two quad channel gigabit nics if you want an uber-supreme router.
Honestly I looked into the little DIY router boxes at one time and thought they were over priced for the poor specs that they had and that you could get a "store" router for cheaper. One thing I will say is that Pfsense is more know for being an amazing firewall (when set up that way).
pfsense is not really an alternative to box store routers, it's more geared toward enterprise stuff. So compared to a proper enterprise router or firewall pfsense is a lot cheaper while having similar functionality. Compared to a simple consumer router pfsense (unless you have spare hardware) will be much more expensive. Also, it really isn't made for wi-fi, it does support it, but it lacks drivers for most modern wi-fi cards (pretty much anything newer than b/g won't work) so you still need an access point for wi-fi. You also need a switch for connecting it to other devices, so by the time you buy an alix box, and access point and a switch you're really not saving any money. Unless you need the features or performance of pfsense you're probably better off with a regular consumer router running custom firmware.
To be honest ALIX is somewhat outdated now, there are better solutions with much more CPU power. But going back to what others have said, yes, unless you need fancy features I'd buy one of the new Linksys routers that officially supports OpenWRT and call it a day.