I haven't used VC4, but the IP2IR, iTach Flex, and Global Connect line have all been working great for me with Crestron for the last 10+ years. Some of the WiFi versions have occasionally been flaky, but I'm sure that's the RF environment they're in.
We always use static IP addresses and TCP/IP clients in SIMPL. If you use direct sockets, connect when you need to send a command then disconnect after the response.
