I want to build my own AR because I can build it to what I want. The PC that I am typing on is one that I built myself and I am happy with it, I put in the time to buy the components and make it my own. If I where to go and get an AR off the shelf then it would not do the same for me as one that I built myself.
if you want to build a rifle that is custom to you, and you have some internal preference for having your personalized gear (which is nothing wrong by any means), that's fine and really great. you learn so much from the DIY approach.
but in terms of practicality and cost-effectiveness, i still think a manufacturer built, stock rifle makes most sense. you get a warranty and customer service. i think the resale value of an AR will end up being proportionately higher than a home-built rifle. i could be wrong about this, but if i were a second-hand buyer, i would rather be buying a rifle made to some professional manufacturer's specs than some unknown rifle builder. again, if you never ever want to sell your rifle, then this is moot. but these are the things i take into consideration. i used to be all about customizing and making my equipment *mine* (for everything, including cars, motorcycle, knives, guns, watches, etc). after a while of buying, modifying, selling... it just makes sense to keep most things stock-ish.
also i never understood giving lower priority to good optics/sights. i think any shooter should place a lot higher priority on optics than they typically do. it seems like the general attitude is "buy nice parts or nice rifle, get optics *some time down the line*. i think that's backwards. i put my money where my mouth is, too. right now my AR is completely stock, with the exception of a magpul grip (for storage space inside the grip). on top is a trijicon ACOG, itself which costs several hundred dollars more than the rifle itself. the rest of the money i dumped into about 2k rounds worth of ammo to stockpile and spare OEM springs/parts here and there. this is a more practical approach, at least for me. the rifle puts holes where i want them, it's reliable to my expectations. i've never put so many rounds down that the components hindered reasonable performance. i could quickly sell the stock rifle and ACOG as separate items and recover cost. this just seems more utilitarian and cost-effective overall. YMMV of course.
