Do you want a true military classic? Or a commercial variant?
CSA rifles are commercially made ‘new rifles’. They are not military grade as far as quality (lots of people had problems with parts wearing out – I think this has been fixed with newer generations), nor are they in true military format (commercial plastic furniture versus lovely Beaver Barff), and some of their rifles come with plastic magazines.
The CZ858 is a true military rifle (hence why it was almost relegated to the prohibited category). Everything except for the ‘receiver’ is military issue. For example, all the parts, furniture, finish (grey enamel), metal magazines, pouches, etc. are as issued and original. Heck if you have a armour’s box all the parts in there will fit a CZ858 except for 1x part (full auto piece), whereas all these parts will not necessarily fit in a CSA variant.
Since the Czech’s made the VZ24 – they have been renowned for making very excellently built military grade rifles that can suffer abuse – hence why the CZ858 is the Cadillac of 58’s. They didn’t sacrifice quality for profits – especially during the Cold War – attention to detail and an excellent product was the result.
The CSA is still a nice rifle, but in my mind it would be like comparing a FAMAE SG542 to a Swiss Arms SG542. If you pick one up – you can tell the difference in quality – everything from the fit to finish.
So end at the end of the day, the CZ858 is a far better military grade rifle than the CSA variant. End of the day - I own at least one of both but my CSA is in 223.