Mine is a PAP2T. I like it fine, but I am sure a Grandstream would be OK too.
I have a couple collecting dust. I remember GS seemed louder, but a nice
loud with great tone.

Its been a long time now since VOIPo shipped the PAP2T. I think the current
ATAs are GS 502 still? The average user likely has a router these days, but having
a built-in router likely helped customers get running sooner without feeling
tricked into needing more hardware.

I kind of miss my old original CISCO ATA 186 I bought as my first ever ATA an
ran it with iConnectHere.com credentials. A month later I discovered Vonage.
I never really met an ATA that didn't work. (OK Zoom and ZyXEL were mediocre.)