The RFX6000/RFX6500 extenders use standard RF per your TSU7000. Not sure if you are using extenders or not, but RF interference, IR emitter placement, the IR codes themselves and duration and timing at which IR codes are sent all can have an impact on how reliable your IR based system may be. That being said, with the proper testing and adjustments if needed an IR based system can prove to be very reliable.

Now as you already own a TSU7000 I would definately recommend that you check out what the Pronto Professional line has to offer. The Pronto Professional line of remotes and extenders (TSU9400/TSU9600/TSU9800/RFX9400/RFX9600) use Wi-Fi versus standard RF to communicate with each other. A given remote must maintain a connection with the extender it's attempting to send commands to otherwise the remote will stop in its tracks.

Quoted from here ...
"To overcome Wi-Fi drop outs Philips have written their own protocol which transmits the commands in a 'packet' formation over the standard Wi-Fi networks. This means a dropout will not allow a macro to only part execute causing systems to get out of sync."

This at the very least ensures that the extenders are successfully receiving a given command providing for a far more robust IR solution than what is offered per the Pronto NG line. I went from the TSU7500 to a TSU9600, so I can attest to this first hand. The Pronto Professional line also supports 2-way communication via TCP/IP or RS-232, ProntoScript and much more. While this is an old post, check out my reply here where I outline many of the benefits when going from the Pronto NG line to the Pronto Professional line.