I live in Maple Shade, NJ. It's close to Riverton and Mount Laurel.
The biggest downside to NJ is the property tax. It's one of the highest in the country, so you need to know that going in. For a 4 bedroom home on a quarter acre, you can pay around $6500/year just in property tax.
On the other side, NJ has lower gas prices than PA and DE (but not enough lower to offset the property taxes).
From NJ you can take the PATCO highspeed line into Philly for about $5 round trip, whereas roundtrip on the Septa Regional Rail from Abington, PA to center city Philadelphia is a little over $10 round trip.
Haddonfield and Collingswood are really nice towns. They've both got a gorgeous "downtown" area with a real town identity. There's also a "Friends School" in Haddonfield if you're looking for a really good private school. Though I think the public schools in both towns are good as well. There's also PATCO stops right in Haddonfield and Collingswood, so you'll have easy access to center city Philadelphia.
If you want to be within a half hour of Mount Laurel, you almost need to live in NJ. But then again, I don't know a lot about the different towns in PA except the ones on the far side (Media, West Chester, Chaddsford -- all of these towns are nice and family friendly with Septa Regional Rail access to Center City, but they'll take you 45-60 minutes to get to Mount Laurel).
Hope that mishmash of information helps. Good luck.