Both communities were build by Orleans. Similar finishes, square footage and monthly fees. Both are very nice. You may want to look at the location of each as a deciding factor. I note that you are from PA. Hearthstone closer to the bridges than Tanglewood. Hearthstone is also located very close to Rt. 73 & 38...basically the same distance to each major roadway. Tanglewood is located off Rt. 70, further east than Hearthstone and closer to the Medford border.
The middle school & high school are the same with each community, only the elementary school would be different.
There is a similarly priced community in Mt. Laurel, Rancocas Pointe. Located less than a mile from Rt. 295. The association also cuts the grass and removes the snow up to your front door. Newer homes but similar in size, layout and finish to the Marlton homes.
If you'd like more detailed information please feel free to get in touch through any of the contacts I've listed below.
Best of luck,
Licensed Salesperson NJ & PA