My Getaria 2.4GHZ Wireless Guitar system (as first described in the OP) arrived today. While I was waiting (about 30 minutes) to charge it up completely, I took the time to read the Q&A on Amazon about this. No serious surprises, the system is pretty much as discussed here. I am seeing various battery life times described by users on Amazon, ranging from 2 hours to 5 hours, but the documentation does not address that question so it's pretty much however long the battery lasts for the user, that's how long it lasts for the user.
I spent about an hour testing; it actually sounds really good, I could recognize no audible difference from using a cable. I noticed no latency with arco, slow pizz, slaps or fast walks (the documentation says < 12ms).
I have an hour gig tomorrow evening that I'll use it for, and then possibly a 3 hour gig on Sunday. I'm anxious to see how it goes, and to enjoy total freedom from cables (my amp is battery powered). I have no intention of leaving the cable home ever, but I do hope not to have to use it much anymore.
Both the transmitter and the receiver can be used while charging, which has me considering bringing along a couple of pocket chargers for longer service time, if I find it necessary. We'll see.