"Fall Ball".. good or bad?

I don't know your league, but the majority of fall ball I've worked is "instructional" in nature rather than competitive.

Fall ball has a wide arc or competitiveness. Playing just to play - against players that are not competitive may not have much value. If the play is competitive and your son is in no danger of burn out - I say play! Just be sure there is ample down time from actual play at some point.

Not to get into good or bad, but nearly all of the most talented kids play in the fall. I can provide proof if needed. Usually the only ones not playing are football players and some of them even play baseball in the fall.

The other reason some might not play is if they are over worked pitchers or injured. But once again, the majority of the top pitchers also play in the fall, just a lighter work load.

It's a great time of the year to play, improve, and get recognized.

From a recruiting stand point, I would play in the Fall. You stated that the season with the team runs until November. It probably ends in November because that is when the N.I.L.'s are signed and recruiting starts its dead period.

Is this with his summer team or High School team?

Most of the H.S. teams use fall ball for training and conditioning along with 1 or sometimes 2 games a week at the most. They use this time to get the players use to each other for the spring season.
As PG Staff said most of the talented players play fall ball of some sort.
One thing to be careful of, if your son is playing H.S. ball and his coach has a fall ball program, many times they frown upon players not playing in their program.

At least here in "NorIL" fall ball is very good, there is a lot of good competition around the Midwest and great exposure. Biggest tournament of the year is in the Fall...WWBA in Jupiter.