It is hard to judge the airline only on the basis o short flights (I am flying regularly for last 3 months WAW-VIE-ZAG), but they are terrible in terms of punctuality... I had to stay three times for a night in VIE as the delay from ZAG was longer than 30-45 min (so as much as flight length!) and there weren't any later flights to WAW.
Plus remember that Croatia is not in Schengen zone, you need to have double security check in case of connecting flights.