The following is from my personal experience with each rifle.
SU-16, cheap, not accurate with 5 different types of ammo we tried, and by the time you spend the money putting on the extras to make it acceptable cosmetically you may as well have just bought something else.
Mini-14, not worth what they sell for. Mine was a 1997 built stainless ranch rifle with a 1:7 twist and while it was reliable with expensive magazines it was minute of barn door and was so overgassed it would throw brass 30 feet to the right hitting other shooters at the range.
I've only shot a T97 once but I wouldn't waste my money on one. Here is why. The rifle shot well and was fairly accurate but it is going to cost you $1000 for the rifle then another $400 for the flat top upper. What do you have after you spend $1400? A rifle with no warranty and no parts availability. No thanks, not for me.
AR180B-2, best non restricted semi auto rifle I've owned for under $1500. As accurate as any other NR rifle we have available to us and mine was 100% reliable. Rifle is light and simple. No need for tacticool garbage. Just buy mags and ammo.
SKS cheap reliable fun but not a black rifle.
CZ series, never owned one but shot a few. Better than an SKS but not a black rifle.
Not sure if I missed any.
If you can't spend more than $1000 keep saving, you need close to double that for a good non restricted black rifle.
Best option for $1000 or slightly over is to buy an AR. Not non restricted but the best black rifle out there dollar for dollar.
Good luck