I just traded my 20" HBAR upper on a Bushmaster lower for a new Kimber. I've always loved the AR-15 but really wanted that new pistol.
Turns out my rifle configuration was not "in fashion" any more. The guy that I traded with said the hot configurations here in Texas were shorty uppers with collapsible stocks. I was going the opposite direction with my AR-15 because I was planning to put a target barrel upper on it. Anyway, just something to think about as you choose your kit for the new AR if you plan to resell it quickly.