The one that has the features you want. Back up camera? USB? Sirius XM? Bluetooth? Touch screen? Remote? Phone app? The sky's the limit. My recommendation is stay with a name brand, that has a long record. My Audivox has had three firm ware updates over the past couple years, i have the touch screen and back up cam, it has the hooks up and controls for Sirius, i just haven't installed, I also have an 8GB memory stick in the glove box, i think i have around 3000 songs, mostly oldies. Pioneer Panasonic JVC are all good and have their fans and detractors.
I'D RATHER GO SLOW THAN NOT GO AT ALL