I have both. 2 gateways and 3 in chassis modules from Prosoft. The gateways are just that, providing network isolated data to a third party on a different subnet. Pure awesomeness!
The in-Chassis modules use the same configuration software, which is just OK. Could be greatly improved but as often as you need it I guess its fine.
The one from spectrum looks like a great improvement in configuration - but can't imagine how it would function any better. I still will try one someday.
I need one that can poll an RS485 loop using ascii commands and responses. Hope these show up on my radar someday.