I just got one of the roller model, and have been using it for a couple
of days. It's a very convenient size and shape for carrying (no clip -
just dump it in your pocket or purse). I filled mine with Noodler's
black ink, and the flow is very good - except I have to shake the pen
to "get it going" if I haven't used it for a while. Otherwise, a nice
wet & even line.
Thanks to Nathan for a useful pen modification, and to Swisher for
carrying them.

(I have no connection to either of them, except as a customer)