They come with 6 different sized ear bits, I think it’s 6. There’s a whole wee bag of them anyhow, but the standard ones do me fine so I’ve not investigated in detail.
IME nokia BT headphones are amongst the best sound quality wise. I have some motorola S805, and whilst they are generally well received, they’re nowhere near as good as the nokias.
Not tried running with them – just walking about town etc really. I like that there’s no wire to get tugged on etc. as I find that quite distracting.
Just tried jogging on the spot in them, seem fine – don’t move about. Not as good as wired in ear buds maybe, but then you don’t have the cable tug issue. I don’t think they’d bother me to run in. I do think they seem to be a good fit for my head/ear shape though. I’ve read reviews of people that don’t get on with the shape – but I guess that’s an issue with most headphones, fit is a very personal thing.