I've heard the sundown neo 10's and they get pretty loud and sound pretty good. Haven't been all that impressed with the PWX's. Solid midbass but not all that loud.
I prefer selenium, PE PA, AQ, and eminence over either of your choices...
Im also curious if the Sundowns are one of the best bangs for the buck. Im about to pull the trigger on them. Was also looking at some JL C5s but the Sundowns I cant stop eyeballin'.