I am thinking of getting a cabinet blaster.
I see there are many sizes and suppliers.

What are you using?
Size of the cabinet?
A 36" wide will do most parts from a car. Except for bumpers/d-shafts/etc.
Brand?
I have an older Trico: really heavy gauge metal.
Oxide or glass bead?
Glass if for softer metals, plastics, etc. Oxide for those cast/steel with rust.
What is the minimum compressor output needed?
Depends on size of the nozzle & size of object. Many comp's can't keep up
with blasting continuously for many minutes, except maybe some screw types or
if you have a hugh tank. They tend to get overly hot after some time.
Are the small table top any good for smaller items?
You'll outgrow them quickly. Maybe good for model trains/etc.
Anything to run away from?
I see there are places that have used equipment...but with something like this unless you know the history it seems risky.
There really isn't that many things that wear with older ones: nozzle/hose/filter/etc. Nice thing is you may find a larger one cheap & then
you adapt nozzles/hoses/filters to suite your need.