I am an independent insurance agent, representing a whole slew of companies... no Geico, State Farm, Allstate etc though, but have a better than average understanding of those companies.
Fact of the matter is, there is no one "Best" company. You and your neighbor are two different people, even if you drive the same cars etc. With the enormous amount of rating factors that go into an auto rate, one company will be great for one person, not good for another. Young drivers, town you live in, how far you drive, and very important now, your credit score (or insurance score... which is largely based on your credit)
Geico can be good, but they are bad in other aspects. They are notorious for giving a great starting rate, but they don't do a full account of the underwriting information until after the policy is issued. Then your 6 month renewal comes out and there is a significant jump. I have also had people leave me to go to Geico because they were saving hundreds of dollars, but in one spectacular case, the company left collision off their 1 year old car. The client found this out AFTER getting into an accident. Imagine the headaches trying to get that straightened out.
The "College" discounts are a funny thing. There are discounts like this that are available through direct markets, but other discounts are only available through agents. One carrier that I represent is also a direct writer and offers the "College" discount. When I tried to get the discount applied to a quote, I could not... but there was another Affiliation discount that I could get applied that the client could not get by going direct.
NJM is a great auto carrier, though they are not the untouchable company that they used to be. Years ago If someone asked me to quote against their NJM, I wouldn't waste my time. Now though, we can beat them frequently even with their "rebate". BTW, their home policies are "Tofu"... nothing spectacular.
The suggestion on packaging the policies is spot on. Doesn't always work, but is one of the best discounts available.