Long story short, but we made reservations at Vila Sole Pomenic in the old town of Korcula, held them with a wire transfer of over $300, and showed up to find out that we had no reservations and no rooms. Boris, the owner, then tried to rip us off (and even disappeared for a while) twice more before we demanded our money back. We did get our money back, but were sans reservations on a Croatian island during high season.
We ended up staying at Apartments Lenni (highly recommended). It become clear from our conversations with them and the tourism board that this was a regular occurrence. I don't think Boris is an evil person, but he's incredible disorganized and a large percentage of his reservations get lost in the shuffle. But his response was reprehensible. Having acknowledged his mistake, he tried to shelve us 2 miles outside of the town then, when we refused, tried to stick us in a room that went for a third the rate we'd paid him.
So, if you're heading to the old town of Korcula, avoid Boris and Pomenic.