My father owns one...
Nice gun for the money. Seems a bit heavier than my older Urika.
I would put the SX-4 in the same category as the A-300... (I own an SX-4 in 12 ga.)
Franchi Infinity is in a similar price point, probably a bit more reliable and easier to clean (as an inertia gun compared to gas-operated)... Also more recoil.