Siva, I live in Livingston so I can speak from first hand experience. There are many positives about Livingston. Some are the residential nature of the town balanced by appropriate commercial and light industrial properties (many office complexes). There are wonderful parks, 2 town pools, and perhaps the number 1 factor for many of the residents is the highly-regarded school system.
I am also familiar with Scotch Plains. In fact I will be having dinner there tomorrow evening with my son, his girlfriend, my daughter and her fiance and my wife. Scotch Plains is also a nice residential town with good schools. It also has a mix of some commercial properties to contribute to the tax revenues.
You will readily see on a map that Livingston is closer to Summit than Scotch Plains and also closer to NYC. Scotch Plains has acess to train service to NY while Livingston has bus service to midtown. There are numerous other differences.
It's really for you to decide which is "better" for your needs. Both offer homes in your price range, style, condition, home size, yard size, taxes, ameneties, etc. can vary considerably.
It would be smart on your part to select a competent Realtor(c) who can show you what you can expect in each community in your price range. Then, when you have the facts, you can decide which is better for your family. In the meantime you can search the MLS free of charge on my website. http://www.GWalsh.com