I know CZ rifles fairly well. They are solid "working" guns and a good value, but they sometimes need a bit of work to make them feed well. They are well built but are somewhat heavy and little rough around the edges. After they are broken in and smoothed out they are very good. The CZ set trigger is not my cup of tea but some guys like it.
The CZ O/U looks to be the same level of fit and finish as their rifles. Nothing fancy but solid. The lowest priced CZ O/U has double triggers while the next one up has a single selective trigger. They share the same stock design, so it might be a small but awkward to move from one trigger to the other. When I shoot double triggers I like a straight grip "English" stock so that my hand can move better to the rear trigger.
Both of them have extractors, not ejectors, so I would guess that the trigger along with some fit and finish are the main differences.