IMO you would be better off playing on a team that gets you exposure.
One PG showcase event gets you a rating by PG and the event may have a few recruiters in attendance. A one day workout and a couple of at bats might not be the best form of evaluating talent.
Playing for a team that goes to PG tournaments, as well as other tourneys, will get your son in front of way more recruiters. It is always best to be seen in person, multiple times, to be evaluated fairly IMO. If a recruiter sees your son do the same thing, good or bad, on serveral occasions he will have a better idea of your son's talents.
Most kids my son has played with the past 4 years have been to all of the PG tournaments in Georgia, Florida and in the Northeast. Very few have done the individual showcases. Most of the kids are now being recruited and committing with major D1 programs up and down the east coast and beyond.