Just wanted to add my 2 cents here. I agree with all the praises from previous posters. Not only is the OL concept a great one, the principals of the company really know what customer service is all about.
I have been traveling the last few times with my 2 young DDs without DH. We've been using ME and not renting a car like we previously did. Therefore, we either needed to bring everything we need or buy it on site since we didn't have a car.
OL has been soooooo convenient. We left laundry detergent, rain poncho, extra water (sorry that's why it's so heavy), ziplocks, food storage containers, dry pasta, toiletries, etc. It really helped me not to pack as much stuff which cut out a lot of the stress of traveling by myself with kids. It gave me peace of mind about things I had access to at WDW without a car and without having to pack and bring "everything and the kitchen sink" each and every trip. And traveling alone with young kids, I didn't want to have a car. It was nice to have ME handle all the luggage and transportation.
Our Locker was always waiting for us at whatever resort we checked into. And I received an e-mail from OL everytime it was picked up and returned to storage.
Let me give you an example of wonderful customer service. The girls and I took a week trip to WDW in Feb 2007 over President's Week. We were staying in a studio at VWL and the night before our flight home, my DD7 came down with a stomach bug. She and I were up all night in the bathroom.
By morning, she was totally empty but very, very weak. She kept crying that she wanted to go home so we planned to fly home as scheduled. We checked in all our luggage at the resort and got our boarding passes. The resort did extend our check-out for an extra hour because of a sick child. We took ME to the airport. DD7 sat and slept in the stroller we had brought on the trip for DD5. We pushed her all the way to the gate before finding out that the flight home was cancelled!!
DD5 was a trooper and watched over her older sister while I tried to find us a flight home. I was on the customer service phone with Delta and on the cell with DH who was looking on-line. Delta had us on an early morning flight that connected twice before getting home 8 hours later!

No way I was taking a chance of getting stranded in a unfamiliar city. All the non-stop for the next few days were fully booked and I could only stand by for them. No way! So, I had the Delta rep book us on the first confirmable non-stop flight which was 2 days later on a Tuesday morning. We were suppose to fly home Sunday early afternoon.
After re-scheduling the flight, we went over the MCO Hyatt to see if we could get a room. DH said it was sold out on-line. And it was.
As I tried to figure out what to do next, we went down to luggage claim to get our luggage. I got one of those luggage trolleys and took care of all the luggage while DD5 pushed her 70+ lbs sister in the stroller. Boy she was such a help that day. We found a place to sit and I could make some phone calls.
DVC MS was closed on Sundays. So, I called the resorts directly. They managed to find me a one-bedroom at BWV for 2 nights on points. Told me to just give my room reservation to ME in order to get back on the bus to WDW.
So, over 5 hours after leaving WDW property, we were heading back. Once we got to BWV and our room, I put DD7 right to bed and I gave Brian or John a call to see where my Locker was and to see if they could drop it off for me tomorrow morning. They had already picked up all the lockers on property and were on their way off property. I told them that tomorrow would be fine but once they heard about my cancelled flight and that my toiletries were all in the locker, they came right back and made a special trip to drop off my locker at the BW. I think I got my locker within 30 minutes.
Brian and John are really gentlemen and they take their business seriously and really put 1000% into it. They are quick to return any e-mails and phone calls. I got locked out of the OL website one time, and John called me right back while he was cooking dinner for his family on the BBQ grill to help me re-set my password.
Yes, the initial costs might be a hurdle to get past. As an educated consumer, we have to do our homework and make sure that we make the right decision for our family and our money. But once you get past that initial hurdle, I think you will find that OL is a quality product and service with a quality company behind it and it is worth every penny. HTH.