Absolutely good on house wine. There will be an occasional dud, but usually it's really good. On the coast, Istria is better known for whites, Dalmatia for reds, but there are exceptions. In the east (Slavonia region), it's whites more than reds. Problem is around Zagreb, where traditionally wine is not that good, but restaurants get wines from other parts of the country - so it depends where they get it from

But, for most part, you won't be disappointed with a house wine. Worst case, you can always ask to try before you order.