It happens rarely that I feel compelled to explicitly advise against staying at a particular hotel. However, the Valdaliso Hotel in Rovinj makes it hard to come up with some positive aspects for the review. I grew up in Europe and now live in the US, so I am familiar with the differences in touristic culture and standards between US and European hotels. Still, even after cutting a lot of slack, you cannot call the Valdaliso anything but an overpriced dump.
For starters, the building in which our rooms were located had neither air conditioning nor an elevator. Sure, A/C is not necessarily considered standard equipment everywhere in Europe, but it sure would be a nice-to-have feature when you're lugging your suitcases up the stairs to the fourth floor (as we did) while it's a hundred degrees outside and about the same temperature inside.
Our room did come with a TV that received the common European channels of the area, but unfortunately every channel had a different sort of reception problem (from grainy or sideways shifted picture to various types of horizontal striping). We are not big on TV anyway and didn't contact the staff about this (though, given my other experiences with the staff, I doubt that the issue would have been resolved in a timely manner).
I typically see my hotel room as a kind of "home base" to which you look forward to after you had a day filled with all sorts of activities. At the Valdaliso, the heat in our cramped room directly under the roof made the nights so uncomfortable that I considered drinking myself into a stupor at the hotel bar so that I'd pass out for the night (but eventually I decided against that idea).
You certainly can't blame the hotel for the Croatian summer heat, and the unfortunate lack of air conditioning may be put aside as "not standard" in this part of Europe. What you definitely can blame the hotel for, in our case, was a noticeable lack of cleanliness. The room didn't seem to have undergone a thorough vacuuming in quite a while (and since the maids probably have to schlepp the vacuum cleaner up and down the stairs this fact is not so surprising after all). There were cobwebs in the corners and under the little desk (and mind you, you don't have to specifically look for those -- these are fat cobwebs and dust bunnies we're talking about here). Also, the area around the room's little trash bin was littered with what looked like old raisins but could also have been something less benign (we didn't further investigate this issue and simply stayed clear of the trash bin's vicinity).
My parents had a room on the first floor which was a little cooler than ours but looked like a dark prison cell. Notably, there was graffiti on the walls of their room that was only sloppily painted over with white paint.
We found the breakfast pretty substandard. A couple varieties of bread, none of which appeared to be too fresh, some spreads, one type of cheese, one dubious processed meat product, and that was it. Oh, there were also severely undercooked scrambled eggs, which we didn't try for health reasons (and I'm not talking about cholesterol here). Orange juice was an especially rare commodity at breakfast. The automatic juice dispenser took about a minute to produce a small glass of "orange juice" (based on its taste, probably made from some sort of concentrate or powder). Consequently, you had to wait in line for a while if you wanted orange juice. On the first morning of our stay, orange juice ran out half way through the breakfast, and the next morning there was no orange juice at all. Not that we had missed much there...
There were two computers in the main lobby that allowed you to access the Internet for a fee. On multiple occasions I found them out of service due to "problems with the server", I was told.
Given all this, I have to say that the Valdaliso Hotel is not cheap, not by any means. For the price of a room at the Valdaliso you actually can get a pretty nice hotel in comparable locations. What probably ticks me off the most is that the hotel owners must make a killing with this business. The place looks like it has not been updated or renovated since Tito's death in 1980. Management is charging a lot of money for poor rooms and service and is apparently reinvesting very little to none of the revenue. That sort of business practice is hard to condone for a place that has so many problems that need to be fixed.
The only positive point I'd like to mention is that the hotel is pretty much right at the beach (pebble and rock beach, like most beaches at the Adriatic). So, if you are mainly looking for beach activities the hotel location is pretty good.
In summary, most youth hostels that I've stayed at provided better rooms and way better value for the money than the Valdaliso Hotel. Other than the proximity to the beach I cannot think of any reason why anyone would want to stay at this hotel.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC