I'm a member/fan of Hertz Gold and now National's Emerald Aisle. What I wish to avoid when traveling is waiting in long lines. Both of these programs allow you to go straight to the car from the shuttle, for the win. I book online, sometimes directly, or through Costco or autoslash, whatever gives me the best price. Having AAA get really helps with pricing as well. Picking up at an off airport site can sometimes be a money saver, but only if it's in the direction I'm going and the access is easy.
There may be other companies with similar programs. Hertz and National have enough options for myour needs.
If booking through PL or HW means waiting in line, it's not gonna happen.