[Viffermike]

A general set of rules, if your car is clean:
- A dealer that sells the same make of car you're trying to trade in is probably going to offer you the best price for it. This is particularly the case with cars less than four years old because a same-make dealer will try to CPO it and increase its profit margin.
- A deal that sells a competing make and model of the car you're trying to trade in will likely give the second-best trade-in value. This is because shoppers looking for a specific new or CPO car will be able to shop a competitor without having to leave that lot -- but that dealer will still make money if either car sells. This is why the BMW dealer offered crap trade-in value for a Subaru WRX in a post above. BMW customers rarely have an interest in a Subaru.
- CarMax is competitive for three reasons: 1). It owns many new-car dealerships across the country, so it can offload what tends not to sell at CarMax locations to some of those dealerships. 2). It offers a relatively seamless process that's worth less consumer value to some, as demonstrated above. 3). The tax-difference factor, which it can achieve largely because of reason 1). above.
- The demographics of the typical CarMax buying customer is very bland: lower to middle class, family-oriented, and not car-savvy to the point of fearing the buying process. Luxury makes, sports cars, specialty vehicles, etc. don't sell well there because those types of customers aren't typically shopping at CarMax.

In light of all of that, your Honda Pilot is a good candidate for a good CarMax offer, except that (as another poster indicated) it's a little old. You likely get a good offer on it only if it has significantly fewer miles than it should. If it doesn't, I would either try a Honda dealership or sell it privately.