Summary
One of the most accessible roguelikes available, Tales of Maj’Eyal is almost more RPG than traditional roguelike, and is completely free to boot (donations can be given to the developers).
Performance & Quality
The Mac version isn’t great; you can’t cmd-tab, parts of the UI can get unresponsive. You’ll also need to specifically authorise it to run with Gatekeeper (by right-clicking and choosing “Open” on the icon.