Hi Scylla,
I started out with a 901, and then went on to a 510, out of the two, I liked the 901 for flavour and the 510 for vapour production.
I feel that was such a long long time ago, although it really wasnt that long in terms of months, however, for me personally the JS has totally spoilt me...lol
I get more flavour from the juice with the 901 adapter, yes, but its a harder draw than the 801.
Im going to give it a day or two before making a final judgement, and will then post a review of my findings on the Janty Club website.