Rosto is a Mexican/Turkish/Lebanese/Slovak fusion concept with one fatal flaw - it serves terrible Mexican food, terrible Turkish food, terrible Lebanese food and standard Slovak food, the latter of which you could easily find at a dozen restaurants on the same block, albeit for a quarter of the price.
Service was appalling. Waitress hovered over us and became aggressive when we tried to shoo her away for 5 minutes so that we could consider our order. Instead, she tried to bully us into a quick decision with her "recommendations" - assuming, along typical Slovak 1950s gender-stereotyped lines, that as a man I would want meat, and lots of it. (Actually, I wanted fish).
After the waitress's lack of English proved an impossible obstacle to obtaining basic information about the menu, the maitre d' emerged to "answer" our questions. Unfortunately, doing so would have required a basic understanding of the menu, a challenge that proved too much for our hero.
Restaurant was completely empty on a Thursday night (which is probably indicative of its quality), except for one other table. The absence of any music in the background meant that we were shut up in a tiny room with only one other table - a set-up designed to ensure that you can hear 100% of the other table's conversation and vice-versa.
If there's ever a nuclear holocaust and Rosto is the only restaurant in the world to survive, then I would consider going back (although I still probably wouldn't). Otherwise, I would give Rosto a wide berth on any visit to Kosice.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.