It's going to be a budget build, done over time as I scrounge money/parts.
I was originally looking at a 20 inch barrel, with flat top upper and a detachable carry handle. Reasons were: Nostalgia and looks(I like the old school AR look), longer sight radius (the build alone will take my "fun" money, so no optics in the near future) and the idea that a 20" ar could fulfill a role my current 16" AKs cannot, which is long range shooting.
But now that I'm surfing around, I see I have options...

Something that jumped out at me is a build they're calling a "dissipator" (no idea why, think its just the marketing name someone made up).
The concept is a 16 inch carbine, with FSB fixed at the end of the barrel instead of close in, giving you a longer sight radius on a shorter, more handy gun.
That would fix my "want longer sight radius" issue, but in a lighter, handier package. As well, I don't have a range around here that goes past 100 yards, so I'm not real sure a guns ability at 500 yards should factor into my decision at all.
Anyone have rifle length irons on a carbine? Thoughts on one or the other?