Hi!
For me it is definitely worth it to upgrade to Preferred room. But, I have a bad knee, and find it a hassle to walk far with my two kids (I go to Disney without my husband, and I go when the weather is very hot and humid; so, the kids being able to walk to the food court, pool, movie on their own is huge for me (they'd get lost if were weren't in the preferred area)). Also, I didn't rent a car on that trip.
I can easily see some people not thinking it is worth the extra cost: if you don't visit the food court and pool area several times a day, and if you have a car, then might not be worth the upgrade. Also, people who stay at the farther most areas (I've heard it is 1 mile round trip walk from one village to the food court; I haven't confirmed that but google maps would show you distances) like it because it is peaceful. It is a beautiful walk - the grounds are very pretty - lots of palm trees, etc.
Good luck! Pros and cons to every decision (for me at least - wish it was simpler)!