I found the specifications for the Thomas compressor here
http://www.gd-thomas.com/product.aspx?id=12084&tp=p .
To summarize
Flow
Viair
1.03 CFM @ 0psi
Thomas
.80 CFM @ 0psi
Max continous pressure
Viair
120psi
Thomas
100.1psi
Duty cycle
Viair
9%
Thomas
Not rated
Max on time
Viair
>3min 3sec
Thomas
Not rated
Weight
Viair
2.4lbs
Thomas
4.4lbs
Outlets
Viair
1
Thomas
2
Current draw
Viair
10a
Thomas
10.5a
Check valve included ?
Viair
Yes
Thomas
No
Yes the external head temp of the Viair will get higher than the Thomas due to its lower thermal mass and the fact that it has more cooling fins to pull the heat from the compression chamber but that is a good thing since it likely means lower internal temps.