Most of the hotels are lately refurbished and totally renovated in the last 5 years, so you might experience some of the best hotels in your life. Prices are reasonable. Boutique hotels and 5-star hotels are great, and the prices correspond with the quality. 4-star hotels are more that you expect and the food they serve is to be remembered.
Lately in Zagreb especially- there are many really private accommodations and the prices are more than affordable. At the seaside- as well, but in the summertime, the great ones are already booked. So, do it on time.