Pony or Little League 10y/o pitching

You actually have more choices (or soon will have) other than little league and pony league. LL and PL fall into the class of recreational baseball and the other options I speak of are travel/select baseball which are classified as competitive baseball. The facts are well know that travel/select baseball has gutted the talent from recreational baseball and from a talent stand point has left some very weak recreational programs throughout the US. Many players start in competitive baseball around 8 years old. My son started at 11. I do think if your son stays in recreational baseball until 14 he's hurting his chances of playing high school baseball. Of course LA is a big place and has some unique situations and this may not apply but I would definitely do some research.

But to answer your question about little league vs pony league. I don't think it would make much difference. The main thing at 10 y/o is to hold (and develop) his interest in baseball. Eventually talent will decide where he plays baseball but at this point WHO he's playing with has a lot to do with it. Where do his friends play?
In a year or two his baseball talent will determine if he should remain in recreational baseball or move up to a more competitive level.
Fungo

Little League is where I would put a new pitcher, if
it is not enough compitition or games then have him
tryout for a travelball team in July. Lucky for you
your son is in a baseball hotbed.

For young pitchers I also prefer LL. It will allow him to stay more focused on delivery, mechanics, grip, etc and not have to worry about pitching from the stretch and worrying about runners.

If it turns out he likes it and does well there will be plenty of opportunities (fall ball, travel, etc) to learn how to pitch while holding runners.

Good luck!

At ten years old the rules are irrelevant to future success. The quality of the local league will be decided by the quality and integrity of the people running it. Find out about the local reputation of each league. Then decide.

I've gone through the same decision.I have the choice to play Pony or Little League as well.I think Little League would be a better league to start pitching in.The fact that the pitcher only has to concentrate on the delivery and control to me is a positive.We currently play in Pony and there is alot of balks due to new pitchers not knowing what to do when the base runner breaks.In our league a balk is considered a no-pitch and runners return to previous base.For every other position,I think the progression/transistion as the players get older is better in Pony.
Good luck with whatever decision you and your son make and please post your results as my son is sort of in the same situation(just a little younger).