To keep steering wheel controls you NEED the adapter but they're SO easy to connect and setup (15 minutes). The HUs that have built in mics are usually crap quality in every way so just don't bother, and for simple/clean looks of the face/UI I always recommend Pioneer. They have some of the nicest HUs for the price, most are BT/HD Radio/3-pair RCA and come with a mic, not to mention USB and the ability to upgrade down the road (gps/etc). The UI isn't obnoxious like JVC/Kenwood/Generics and also the RCA pre-outs are between 2v-4v for best signal to the amp(s), I plan do get their AVH4100/4200 down the road simply because it has anything I could actually use while not breaking the bank.
Pioneer also makes (or made) an amazing 1DIN HU that was in their "Pro" line of equipment, but for something simple and "elegant" with the highest quality of anything under $600 you would have to spend $1400 for something similar. *(I searched and I think they only did a limited run and they have a habit of making "outdated" hardware a pain to find.)
Anyway, if you know how to use wire cutters/crimpers/dykes (strippers hehe) and have good quality electrical tape then you should be able to wire it up in under 2 hours (dash should be out prior and 2 hours is from start up to tuning the system).