Before buying the GLXD16+ I was using a very good professional rack-mounted wireless system. The sound and reliability were excellent, but for my current setup the rack format was simply much less practical.
The GLXD16+ has been a great solution. Having the receiver directly on my pedalboard makes the whole setup much simpler: one less rack unit, fewer connections and everything I need is right in front of me.
Most importantly, I have not noticed any loss in sound quality. With bass this is particularly important to me, especially in the low end, and the signal sounds full, clean and natural. The latency is surprisingly low and, in real playing conditions, completely unnoticeable to me (even on bass).
Battery life is another major advantage. It is exceptional and easily covers rehearsals and long gigs without making me worry about recharging during the day.
One feature I particularly appreciate as a bass player is the possibility of pairing two transmitters with the same receiver and storing a different gain setting for each one. I regularly use two basses on the same pedalboard, one (low signal) passive bass and one 18V active bass. I can set the correct input gain for each transmitter, and when I change basses the levels are already perfectly matched. No need to change the gain on the pedalboard or compensate somewhere else in the signal chain.
The receiver itself is solid, integrates perfectly into a pedalboard and can be powered from a suitable 9V pedalboard supply. The built-in tuner also really useful in LIVE.
For me, this is the biggest strength of the GLXD16+: I get the sound quality and confidence I expect from a professional wireless system, but in a much more convenient pedalboard format.
Not inexpensive, but for a gigging bassist using a pedalboard, absolutely worth it.