Agree with goofy4tink's assessment. I'd just plan on 2 hrs from exiting the aircraft to getting your room key. I certainly wouldn't have an ADR too close to your scheduled arrival ... your plane could be delayed, you could end up with a lengthy DME experience, etc. Keep in mind that even if you had a town car waiting, you'd have to wait for baggage and then it is at least a 30 min drive from MCO to a WDW resort. Using DME may only add 30 min or less to your trip unless you just had carry-on.
Anyway, its one of the perks of staying at a WDW resort.
I've used it 3 times ... yeah, it can be frustrating waiting in line and then waiting on the bus again, but you eventually get there. It's better than being at work. LOL!
We rented a car in March, but used DME to get to the resort; we saved money by renting from one of the WDW locations (airport rental was $65 more!!). Disney also handled our luggage, so that also was a big plus.
Anyway, just plan on it taking awhile and if you get there sooner than expected, you'll be ahead of the game.