One from Lowes and one from Home Depot.

Both are oil lubed, cast iron pumps, 120 volt, belt driven, uprights.

The Kobalt brand from Lowes is rated 5.7 @ 90psi and has a 30 gal tank.

The Husky brand from Home Depot is rated 5.8 @ 90psi and has a 26 gal
tank.

I'm leaning toward the Husky from Home Depot, but, should the 4 gal tank
difference compel me to get the Kobalt from Lowes?

My inclination would also be to go with the Husky brand. Both units are
close enough that the size of the tank and the difference in cfm are not
going to be very noticeable. I'd be more concerned with duty cycle ratings,
acoustic ratings, and warranty coverage.