I have been pleased with multiple RB750G's (one is going on 150 days of uptime!). I am looking to simplify things a bit and replace the 750G and Ubiquiti AP I have with a single 2HnD. However, I want it to have two SSIDs - one guest and one regular network. Does RouterOS support multiple SSIDs on a single radio? Can I create a VLAN and then attach a wireless network to a VLAN? I tried researching this a bit but couldn't find much info.

Yes, this is possible with Virtual AP.

http://wiki.mikrotik.com/images/5/5f/Cr ... Campus.pdf

That seems to be what I'm looking for, great!