I'm looking to reserve a rental car for leisure use (first time in a long time or ever) at MCO soon for 4 adults and a baby in a car seat from Mon - Thu.

As I usually only rent with Budget, Thrifty or Enterprise, I've very little experience with a program that let you pick your own car. Is National the only one with Emerald Aisle that lets you potentially upgrade to a higher class car than you've reserved? As I've rented with National only once or twice before, I don't have Executive or higher status.

I've read the FAQ and the thread on "Cars at MCO", and there's a bit of an inconsistency regarding self-upgrading to a higher class than reserved. The FAQ thread said that it's generally not okay to do so without an agent's approval while the "Cars at MCO" thread mention people easily doing that, getting sports cars and what not. National's web site even says to pick any car from the aisle if I've reserved a car at a Midsize price.

And is the 2-reservation game the "right" strategy to see if I can get a free upgrade to a minivan or standard SUV with a midsize reservation (while having another reservation with the minivan or standard SUV as a minimum size reserved)?

Are there any other tips to book this for cheap? I'm thinking of booking through Chase Ultimate Rewards as they have a discounted redemption, but I saw that priceline.com may be a cheaper way to go.

Any tips/anecdotes (that were not mentioned in the FAQ) would be greatly appreciated.