That 18" Miraco is actually a pretty darn nice bike. Compare it to last years offerings, this 2012 model is a major improvement. It's got the cassette driver system, the ratio is about right, the aluminum frame looks to be super light. It's drilled for a Gyro should want to upgrade the headset with one. Oddessy grips are very popular, as is the pivotal style seat. The white half-link chain is the bomb these days, so that is very cool. Black Label is Miraco's parts brand, so not great, but appear to be serviceable. The single wall rims sound light to me, but your son is probably a fraction of the weight my teen is, and likely not to be casing stair jumps and bending rims for a year or two
You might consider getting fiberglass pegs, that will save a couple more pounds, and slide well on rails and so forth. Duro is not very popular, so the tires might be a cosmetic upgrade at some point, and maybe the pedals too. Oddessy is all the rage. The handlebars are a little on the small size, but probably fine for now. I'll bet he'll want a 20" bike before he needs to upgrade the bars.
All in all, I think that REDUX is a pretty nice ride, and the weight can't be beat without going into a BMX race bike, and those are fragile and ill suited for street use. Compare with the FIT 18'':
http://fitbikeco.com/18-inch-black/