modbus tcp/ip as control what are your thoughts

I have an application that will have 2 drives, 1 G306 HMI, and 1 compactlogix PLC all on Ethernet.
My question is is modus tcp/IP OK for control? the compactlogix doesn't speak modbus natively so we have to either buy analog cards for the PLC or speak modbus tcp.
I was planning on bridging through the Red Lion G306. This is a water pumping application so speed is not going to be an issue.
I don't know much about modbus. I have talked to a few guys who say modbus is the only way to go. Then others that say it is just another CSP/PCCC it will work but you could have issues with controlling a drive from it.

I plan on hardwiring the start and stop commands from the PLC.

We used a G3 as a gateway between an L35E (EthernetIP) and a third party PLC (that only talked ModbusTCP/IP) to communicate control signals. The only issue we experienced was the speed of conversion. Otherwise, if speed is not an issue then it should work fine for you.