My experience with Alamo on Maui was horrendous. I waited in a queue for about 30 minutes before getting to the counter. I got a really over-the-top, full-of-lies, hard-sell on additional insurance I didn't need. Then when I got to the car, it was missing a third of a tank of gas. They claimed it was just the gauge. I called them on it and pulled up to their re-fueling station where a guy apparently pretended to put fuel in the car, but claimed it wouldn't take any because it was already full. Amazing that I was able to fill it completely up during the week. Alamo in Kauai on the same trip was fine, though.
The last time in Maui we rented through Avis (via Priceline) and it was one of my best rental car experiences ever. I was in-and-out at the check-out counter in about 2 minutes with a brand new car with no hard-sell for insurance or upgrades.
If I was not using Priceline, I would avoid Alamo in Maui regardless of price and I would use Avis unless their price was significantly out of line with the others. That's my personal experience - your mileage may vary.