Hi all:
This monitor allows selecting Adobe RGB mode, and supposedly is factory calibrated (I think it came with an inspection certificate certifying Adobe RGB mode accuracy)......Should I now change this to what I used to use, namely Adobe RGB, so they match? I am a novice in Color Mgt, but have been fortunate in achieving prints that match my monitor.
The answer to your question is, unsatisfying, it all depends. If you have a good printer, and want to be able to use its entire gamut, stay in PPRGB. If you weren't having problems with colors that were in the PPRGB gamut and not in your printer gamut, making your monitor gamut bigger like you just did will make things better in that regard, not worse.
OTOH, if the reason you went for a big gamut monitor was that you were having difficulties that stemmed from not being about to see on your monitor all the colors in your image, that situation will improve but not resolve if you stay with PPRGB as your working space.
In the absence of a compelling reason to switch, I'd suggest staying in PPRGB.
We have a resident color management expert, Andrew Rodney, and he'll probably chime in here. He's good. Listen to him; I'm just a reformed color scientist.
Jim