We use GXS for one of our VANs. Pricing is a little hard to compare because
we're on a flat-fee pricing structure that allows up to x-number of
kilocharacters per month. They're our highest bill each month, but they are
also the VAN we use for our biggest customers. I can't remember the last
time they had down-time or that I had to call support, but I remember them
being very helpful.
My biggest complaint is I wish I could figure out how to connect to their
FTP servers directly from the System i. They have some archaic FTP server
that doesn't accept the PROT P command to secure the connection; in fact, I
can't even upgrade my PC software at this point because future versions use
PROT P! Otherwise, we've been happy with them.