They are definitely different than cattleya.
I kinda usually get a touch of asstringency from P. cattleianum and some sweet flavor that is sometimes remniscent of strawberry.
P. firmum is a pretty sweet and slightly tart species without any astringency. It's definitely a unique flavor and it's really hard to say much else beyond that as I feel we all can pick up different flavor profiles. There's been a few threads on here where people talk about them and apparently they are one of the better tasting Psidium spp.