I had a SU16 CA and I really liked it. The CA is or at least was the only model we could get here at that time.
It was light and accurate and it took AR mags. What's not to like? I bought mine for camping.
Just realize that it is not some type of battle rifle. It does what it was designed to do very well, so don't go adding a whole bunch of "tactical" crap to try and make it something it's not. It will serve you well as-is.
The only improvement I suggest is to buy a take down pin that has a pull ring on it. It makes take down so much easier.
“If ye love wealth better than liberty, the tranquility of servitude better than the animating contest of freedom, go home from us in peace. We ask not your counsels or arms. Crouch down and lick the hands which feed you. May your chains set lightly upon you, and may posterity forget that ye were our countrymen.” ― Samuel Adams