serialinc vs powerlinc modem serial

[n8huntsman]

I'm planning to by my first HUB and other Insteon devices. I currently have a URC (universal remote control) setup that sends serial commands via the MSC-400 and MX-5000 remote. I also have several devices that respond to serial commands. I'd like to be able to use my remote to send commands to the Insteon network, and also be able to set up scenes in the HUB that include some serial commands being sent to other equipment.
I've read the manual for the serialinc but it's a little vague. I also see the serial Powerlinc Modem, but I can't even find a manual for that. What is the difference between the two. The powerlinc is much cheaper - $80 vs $150 for the serialinc. I'm sure I'll need at least two to accomplish the above so I'd rather spend $80 each if it will work.
Thanks

[stusviews]

The serial PLM will allow you to use serial commands to control INSTEON devices. The SeriaLinc has that ability and, in addition, lets you use INSTEON commands to control serial devices.