A lot to like about it: lots of puzzles included with the demo, control over piece shapes and sizes, the tray feature, etc. Not so fond of a some of the default settings -- when's the last time you started a jigsaw puzzle IRL and had all of the pieces come out of the box oriented correctly?

Then there are the reasons I won't be buying the full version (nor any puzzle packs): working without a mouse is a non-starter because you can't rotate a piece while holding it, the interface is glitchy (not to mention decidedly non-mac) -- creating new trays often leaves ghost pixels, opening and closing trays or folders doesn't work consistently, it just froze completely, forcing me to restart my laptop.