It’s Chromium-based, so, of course, it’s slow. Specifically, search is excruciatingly slow, removing an album from your library redraws the whole page, and—most frustratingly— as soon as you lose internet connection, your perfectly nice and readable page get replaced with “Artist pages are not available offline”. It’s a list of tracks and albums which is updated (at most, on average) several times a year, why require connection to continue showing it?

Not Mac-specific, but extremely weird: sometimes Release Radar playlist has tracks by wrong artists with the same name. I don’t think a recommendation model would use names instead of IDs, so it probably means that track was first ascribed to a wrong artist, and that’s... even worse?