[MustGoFaster]

Speaking in general terms:
Vertical tank units take up the least space.
For enough power to run a die grinder without long waits a 220v unit in 3+ HP is best
2+hp units in 110v use high speed motors and make tons of noise.

For the use you describe, I would say, a 220V unit from Home Depot or similar in the 3 hp range should keep you happy.

Just remember "power out" = "power in - a few %".
High power at low voltage(110V)= high speed low torque and high noise.
High power with more voltage(220V) nets more torque and lower speeds. Low speed = less noise.