I've used Advantage in other locations and never really had a problem other than a guy in PHX trying to upsell me hard.

Been about 3 years since I was last at LAX but I took a deep breath and rented through Fox (which also has a lot of negative reviews). Ended up being an awesome experience with no line, friendly service, great price and best of all, brand new Mustang convertible with under 3 mi on the odometer. So YMMV!