They are both going to be similar build quality so the only things to decide are...
Size - is the smaller form factor needed or decided with the single vs. twin
Cost - If your budget is tight could you spend that extra $$$ on something else you want?
CFM - easy to compare, for your desired use either will work wonderfully , the twin will obviously shorten the time to air up tires
Duty Rating - IIRC the twin is 100% and the single is 50%, unless you are providing air for an entire expedition worth of vehicles I don't think this is much of a concern.
FWIW I have the Twin and love it, however its a lot of money for something that only gets used a half a dozen times a year (ok maybe more if you get out a lot)......but hey I also have a 40" LED bar that is a total economical waste.