to the op, my son went to Pomona and played for Pomona-Pitzer. He was also recruited by Amherst and a number of other LAC, ivy's etc.
Academically Amherst, Williams, Pomona, Haverford, and several others are pretty much equals, all typically top 5 ranked academic schools, certainly top 10 and very much on a par with Stanford or any of the Ivies.
Pomona is a very short drive from downtown LA and the town of Claremont is lovely but very small. Students usually escape to LA or Pasadena but there are lots of activities on Campus.
As you may know the Claremont schools consist of 5 colleges that share resources so you can limit yourself to your one school or take part in the resources of all 5 to a major extent. each school itself ranges from about 900 (pitzer) to 1500 Pomona.
YOu've got great Los Angeles weather, great education. Amherst certainly the equal academically, my son just didn't want to deal with east coast weather.
Level of baseball in SoCal is great and even for D-3 always scouts at the game.
I will admit though, I was not personally a fan of the Pomona coach - send me a PM and i'll fill you in. Also, when my son was there, other than the head coach, they essentially had no staff, I think that has seen a change in the last couple years. Facilities are very nice at Pomona, espeically for a D-3
Only spoke briefly with Amherst coach, he's kind of an institution there as I recall. Haverford coach was a great guy as well as the coach at Tufts.
Williams is another similar school to consider as well as Wesleyan, Haverford, Swarthmore, Johns Hopkins, Tufts. Can't go wrong at any of 'em I would think.
Bottomline between Pomona and Amherst is, as someone pointed out above east coast vs. west and all that goes with that.