I've got a Colt lightweight (other than the Kool-Aid stains, it's nearly the same as the Bushy) and this combined with a DD rail system makes for an extremely light and very versatile setup, IMO. If it's not my favorite, I'm trying to figure out which I like better. Maybe the Dissy with the chopped A2 barrel...................................
Heat up and cool down may cause some POI shifts, but you need to evaluate your needs and if pinpoint accuracy is a need, then maybe the light weight barrel isn't what you want. If you want MOM (minute of man) accuracy through a large string of shots within a reasonable combat range, it will do you well. If prolonged carry is an issue, I'd give it a hard look. I toted an M4 type upper around in a carbine class and after 8 hours of intermittent carry and shooting, it gets heavy.