I’ve been using PlantNet over iNaturalist. One reason is that PlantNet gives confidence scores for identification. In general PN seems very good for European plants.

I haven't used PlantNet though I've been working on learning plant identification/taxonomy and have been using iNaturalist. Their models are limited by inputs, if you've got a wild angiosperm that's flowering it's pretty good. With human cultivars, even with flowers it's not always great, though no shade there, that's what I'd expect for visually trained models that focus on plants in the wild. If you aim it at a leaf there's not enough visual data to categorize, if you aim it at a full plant it's so-so. I mostly stick to flowering plants and have an easy time.

I try PlantNet when Seek can't identify something. It often feels more successful because it always gives a list of possibilities, but when the top answer is like 40% probable I don't actually know if it's doing any better than Seek.

Downsides are that it requires service, and obviously it doesn't work for animals. Seek works perfectly in the middle of the wilderness with zero service, it always feels incredible.