(I have lots of thoughts about rental strollers)
Well I would first make sure you know that you shouldn't leave anything in the stroller. It's amazing how much stuff people DO leave in their strollers, but considering we've now had two things stolen from a stroller and one thing stolen after we left it for 5 minutes on a bench (never turned in to lost and found = stolen), I don't even leave water in the stroller.
Also, there's storage space behind the seat and under the seat of the rentals.
All that said...
I didn't get a pic of the strollers rented during our trip last week, but they are the same as they have been. We got two of the newer strollers...brighter color and cleaner, but the same.
The back of our rental in '05:
DS at 2.5, in '06:
And all *that* said...the time that little ones (and big ones) need the stroller most is during sleepy mornings and nights, IMO. The early trips were only day trips, and we could wear him back to the car, so it wasn't a problem. But when he was 3.5, we stayed over and only had the rental stroller, and it was a problem. DS was excited enough in the mornings, but I ended up carrying him (b/c I didn't want ot take an hour-long walk as he dragged along), and it was NOT fun.
So as relatively nice as the strollers are, I'd make sure you had something for morning and evening before you get to the rental area...
It has been said, however, that they will store your own stroller for you, while you rent one.
Also, the free Disney Visa strollers are obviously a great deal, BUT you give up precious time each and every morning, waiting in the line to get one. If you go that route, make sure you're in a line close to the stroller rental (to the right side in DL and DCA) and have the renter just jet over there to be among the first in line).