I currently have my map about half full of caps. Getting caps in is easy and they stay in firm. The board itself looks good. I've had no trouble with the strength and durability of the board, although I think if it was a little thicker it would offer some extra peace of mind, as I feel a little nervous that it's going to break when I handle it. That's probably just me though. It objectively seems plenty strong as is and everything I've found from a DuckDuckGo search says Baltic Birch is strong.
I'm actually from Rhode Island and would have rather gotten an RI one, if there was some effort put into carving out the Narragansett Bay. I get that there may be concerns with the right part being too thin, but at least carve out some simple geometry. It's such an iconic part of RI's geography. Other states have a fair bit of detail to their borders/shorelines and thinner parts, like long Island from the New York one, or Cape Cod in this one. I work in Massachusetts, so I brought it to work to hang up there instead.