I have used Nova three times since 2018 and I highly recommend them. Most recently, I rented in downtown ZAG and returned in Split; the car was brand new. I have also rented in and out of SPU, as well as pickup in ZAD and dropoff at SPU. Good cars, great rates, and no BS/scams. I always buy the premium insurance because it is a small price to pay to avoid any possible issues or unpleasant surprises, but I have not heard any horror stories about Nova from people who don't. Just be mindful of the rules for cross-border rentals and make sure you select that option.