OP,
Here's my opinion based on many, many such conversations here on this forum, and lots of personal experience.
Your options at 120 volts are very limited, but much better than they used to be. In the 30ish gallon size, your options are either oil lubed, or oilless.
As far as oil lubed go, your options are basically big box store models (think Dewalt, Husky, Kobalt), very similar models from the likes of Tractor Supply, Northern Tool, Grainger, etc. and models which may be sold by any of the above but share brand names with historically reputable compressor makers like Quincy, Ingersoll Rand, Campbell Hausfeld, etc.
Depending on how any of the above are designed, and the combination of motors and pumps they use, they're all going to make somewhere between 5 and 7 cfm at 90 psi. The ones at the high end of that range are going to require a 20 amp circuit, and will use every bit of it. They will all be really loud. Nearly all of them are going to have a limited sized air outlet, usually combined with the pressure switch/regulator manifold rather than a dedicated bung coming from the tank. These will run you between $400 and $ 1,000 depending on where you buy it and whose name is plastered on it.
The alternative to the above is an oilless model. The highest performing models in the portable, 30ish gallon tank range are advertised as "2 hp", and they will max out around 5 CFM at 90 psi with the best of them slightly over that (we're talking a fraction of a cfm here). The biggest benefit of these is that they can be made (relatively) quiet. At or less than 70 dB in many cases. And of course you'll never have to change the oil, but there will be a relatively limited pump lifetime. All the same limitations with regard to the small outlet orifice apply to these as well. These can be had for between $400 and $750 depending on the same factors listed above.
The only real variables in all of this are max pressure (this will range between 120 psi and 200 psi), max output (between less than 5 and just over 7 cfm) orientation (horizontal vs vertical), max current draw (divided into those that will run on a 15 amp breaker and those that will require a 20 amp breaker) and... color.
If you have specific requirements/constraints based on the above options, I'm happy to provide some more specific examples. Knowing only what you have stated so far in this thread, and assuming you want the highest output possible (but not knowing your popet options), I would recommend the following:
If you want to goi oilless, I would get the
26 gallon fortress oilless from Harbor Freight and call it a day. If you have more cash and want slightly higher output with a lower max pressure, look at the "2 HP" California Air Tools models (there are lots of variations based on tank size and material)
If you want the absolute highest flow you can get from 120 volts (assuming a 20 amp outlet) and you don't care about noise, my answer is this
Quincy or it's
horizontal equivalent, or if you're lucky and can get a good deal or free shipping, any of the other compressors identical to the Quincy such as this
Chicago Pneumatic or
this BelAire or this
Atlas Copco or this
ABAC or the older version of the same model such as this
Carlyle or this
Napa.
Good luck.