Welcome to wallethack!
As far as POM, some like them the most as they are denser than PBT. However, it's definitely easy to find affordable rough PBT keycaps (banggood sells Keycool white blank sets for $17, free slow shipping), which I think are my favorite. For more compact boards, I suggest taking a look at the FC660 series, which are known as some of the best-built compact boards you can buy.
Either way, enjoy your stay!