I've been there twice. Both times I've bought great tarts (once pistachio and once traditionally. Both were good. Same with croissants and sweet buns. I can't complain about quality.
Unfortunately I had an impression that the lady wasn't very friendly... and just because I do not speak French... This is the only thing that left a bad impression on that place for me....
Le pain est toujours délicieux chez Kayser. Ce petit Kayser est un endroit agréable où nous sommes toujours extrêmement bien reçus. Tout le monde y est extrêmement gentil...