Marco.org

Enterprise: You make a “reservation” for a general car class (“Compact”, “Full Size”, etc.). But when you show up, they’re out of everything, and you’re stuck with something that’s not even close. In my case, my “Premium” (“Nissan Maxima, Toyota Avalon or similar”) was interpreted as a Mini Cooper. And while I enjoy driving Minis, they’re absolutely not “similar” to a full-size, 4-door, high-performance sedan. (I needed more cargo space than a Mini offers, so they “upgraded” me to their only other available vehicle: a giant SUV. Thanks a lot.)
Zipcar: You get a list of the cars available at each location, and you reserve the exact car you want. You know whether it’s a Mazda3 or a BMW 328. You even know its color and license plate number ahead of time.

Enterprise: Despite the nice Japanese cars advertised on the website, most real-world cars stocked are cheap, lifeless Chevy Random Numbers or Chrysler Nothings.
Zipcar: Most cars stocked are desirable models within their respective classes.

Enterprise: You have no idea what audio capabilities the car will have ahead of time, so if you’re planning to listen to podcasts or an audiobook on your road trip, you probably need to burn a bunch of wasteful, single-use CDs.
Zipcar: Nearly all cars have aux-in jacks (each car’s listing tells you whether it has one), pre-wired with a 1/8” stereo male-to-male cable so you can plug in nearly any audio device you want. The plugs are even shaped to accommodate first-generation iPhones.

Enterprise: You can only pick up and return cars during limited business hours, and they’re closed on Sundays. It’s therefore impossible to rent a car for only Saturday and Sunday, and if you’re arriving home from a trip later in the evening than the branch’s closing time (usually around 6 PM), you need to book the rental to include the entire following day.
Zipcar: Pick up and return cars any time, 24/7.

Enterprise: Minimum 1-day rental, but since they’re closed on Sundays, you often need to buy more than you need. Calendar days, not total time, are charged: renting from Monday, 9 AM to Tuesday, 8 AM is a two-day rental.
Zipcar: Minimum 1-hour rental. But there’s an unfortunate maximum of 3 days. Billing is done by the half-hour, and the day rate is truly 24 hours: renting from Monday, 9 AM to Tuesday, 8 AM is a one-day rental.

Enterprise: Cars are kept in front of a sketchy office in a bad part of town. Fake smalltalk with the employees is required when picking up and dropping off cars.
Zipcar: Cars are kept in lots or garages in upscale urban-residential neighborhoods. Pickup requires, at most, telling a garage attendant which car you need. Dropoff requires no interaction whatsoever.

Enterprise: Picking up takes a half hour (assuming there’s no line) of paperwork with the paranoia-inducing clipboard walkaround. Every scratch and scuff are stressful: Is that big enough to count? How about that? Did I do that?
Zipcar: Picking up only takes longer than a few seconds if a garage attendant needs to get the car out. You’re supposed to do a quick look around for noticeable damage and call them if you find any. I never have.

Enterprise: At the last minute, they scare you into buying high-priced add-on insurance.
Zipcar: Reasonable insurance is included at no charge.

Enterprise: Gas isn’t included, and their “return it with as much as you got it with” refill policy is likely to cause you to buy more gas than you use. Alternately, they’ll fill it for you for over $4 per gallon. Either way, you end up paying more for gas than you should.
Zipcar: Gas is included at no charge — there’s a gas card in the sun visor of every car. Fill up with the card when you need gas. Easy return policy: you must return it with at least a quarter of a tank.

Enterprise: You must pay any tolls you encounter in cash, so you not only need to have enough cash on hand, but you usually need to wait in the much slower and longer lines for the cash toll booths.
Zipcar: All cars have EZpass, with charges automatically passed through to your account.

Enterprise: My most recent Enterprise car’s exterior and glass were covered in salt residue.
Zipcar: The cars are always clean, being detailed regularly by their garages’ staff.

Enterprise: Unlimited mileage, except in some states.
Zipcar: Limited to 180 miles per day. (Enterprise wins for very long trips.)

Overall: Enterprise is so expensive and miserable that I think I might start limiting my trips to 3 days just so I can use Zipcar instead. I wish Zipcar would extend the limit to 4-5 days, but I understand why they don’t.