I have been using the same arguments as the OP. Great idea, but seems fairly pricey, etc.
Well, we took a trip in May...and when we got back I unpacked and put all the clothes away right away (did laundry before leaving, so everything was clean and easy to unpack). Then I had that "other bag" -- the one with all of the random "stuff" in it. This is a lot of the stuff that I would have put in OL. Well, that darn bag sat here for three weeks before I got all of those little items put away.
So that made me think...hmmmm....maybe OL IS worth it. I then talked about it to DH and he said..."you must just have an extra $100 burning a hole in your pocket. That extra bag is not the big of a deal...save the money."
Well, we just got back from our August trip. We returned one week ago. And as I am typing this, I am staring at....yup, the "stuff bag" which is still sitting here. Haven't even attempted to unpack it yet.
So when I finally get around to unpacking the "stuff" - I am really going to look at it and see how much of it would stay at WDW if we had OL. I read the posts like Jean's, where she is packing just clothes, etc. and think---yeah, that would be heaven! But then again, I have three kids, so I wonder how much "stuff" we would actually leave there.
My guess is that I will soon cave and join OL.