SuperMicro's ILO and rack mounting hardware were really poor a few years ago. Has that changed? Keep in mind the big brands have improved those parts since then, so unless SM made amazing progress, they're not a drop in replacement.
Sure the software/tools could be nicer, but I've not been overly impressed with the competition. At least HTML5 has replaced the pain of ancient buggy java solutions that waste 5 minutes over a slow connections with sandbox permissions, java splash screens, and some awful client that's mostly VNC, but with a hacked up auth system.
From what I’ve seen, Supermicro is no different - they use Avocent hardware like everyone else. Everything just depends on what generation of controller they ship.
EDIT: as an example, the iDRAC on my Dell R210 II’s, the IMM on my Lenovo TD340, and iLO 3 on my HP ML10 are all the same generation of Avocent hardware with few differences. My Dell RX20’s have newer OOB modules and suck less to work with, but so does comparably new hardware from other OEM’s because they’re all made by the same damned company.
In about 5 years, maybe I'll replace the ones I have at home (admittedly, I really should just do a blade server at home -- it'd probably be less power draw!)