Right now, I have 2 of the $20 Quansheng radios. The Quansheng UV-5R+ I have is running the F4HWN v2.8 custom firmware, and the RadTel RT-600 (a direct clone of the UV-5R+) is running the IVJ v3.20 fimrware. The mods to AM receive on both of these custom firmware sets make the radios great airband receivers with fast scan speeds. My SDS-100 isn't the greatest for VHF, so that's the reason I grabbed these units.
This is what the F4HWN firmware looks like in single-receive mode: