J-Bonsai has been around for some time. It's owned now by
Yoshihiro Nakamizu and part of Bonsai Network Japan. He does a lot of
bonsai stuff in Japan, including
bonsai tours. I ordered a pot from them a very very long time ago. I vaguely remember the transaction--which involved a bank transfer and a month long wait on the shipment.
The J-bonsai site has been around a while in one shape or another, used to be primarily stock trees and semi-finished trees for sale. Impractical mostly for buying those trees in the U.S., unless you want to wait on the importation process to grind ahead. I think there are some folks who have done that, but they're not numerous.
I don't really see any reason to order stuff from there, as most of the things (with the exception of some of the trees) can be found more immediately here in the U.S. But if you have a craving for "Japan centric" stuff, there's an
argument to be made otherwise
Not sure about the fromjapan site. Looks to be following J-Bonsai's model.
I don't think either is out to rip you off, but you'd be ordering from Japan, with associated import fees (which could be expensive depending on what you get) and delay in getting whatever you ordered.