The P2K can do Modbus even better than the 1400 and doesn't need the breakout board for RS485. I have one doing MRX/MRW to Yaskawa VFDs and it is nice. One twisted pair and some relatively easy keyboard magic gets you all the data both ways. I did have a serial port failure on that system and had to replace the CPU, but the RS485 wire was buried 700' to the pump house and took a lightning hit. I installed a comm port isolator along with the new CPU, but for local wiring, you may not need that extra precaution.
The wiring here is pretty much local. Given that I have to install a GSM modem in this system, I figure I might as well do everything via ethernet. Modbus is just fine, but I'm going to use drives that get stocked locally in our only supply house. That means Eaton GS1 series drives. Honestly, I've heard some good stuff about them. I am thinking that if a click can survive that long in there, a p2k should be fine. Plus with P2k there are a LOT more options as far as IO and communications.