@DeuceoneRadio great job on the research. I guess I have a little different philosophy on continuous power to the radio.
I don't do it much, but sometimes I reach in the truck and turn on the radio briefly. I don't feel like pulling the keys out just for that. Maybe I'm just lazy.
In the Houston area, the Memorial Park repeater and the Channelview repeater both still get some traffic. Not as much as when linked but still you can have a nice chat every once in a while.
I second what @WRHS218 said. Once you join Texas GMRS Network you will have access to a lot of repeaters, many of which are not listed here. MyGMRS.com has a much better forum though.
I've been using a UT-72 with an AT778-UV for more than an year now and have not had any problems. I almost always get good reports. When I don't get a good report, there is usually an obvious reason like weather, distance, trees, buildings, etc. This is a very inexpensive setup and I'm quite pleased with it.
LOL! I could have given a better explanation as well.
GMRS is a "channelized" service. As such the frequencies it's allowed to transmit on are hard coded into channels. When in Memory(channel) mode, you are locked down to transmitting on only the approved frequencies and are therefore allowed to transmit. In VFO mode, you have virtually infinite frequency adjustment in the band as Steve indicated. That is why you can only listen in with VFO mode but you can transmit in Memory mode.