Has anyone done an excellent tour they'd recommend?
When I toured the Uffizi Gallery, I pulled up Rick Steves' audio tour on my iPhone. (It's also available on Android or any device that can play a podcast.) On its own, it takes 48 minutes, but you stop and start as you move from one room to the next. I was in the gallery about 3 hours.
Lawrence gave you great advice. Just use Rick Steves and save money. And then take that money that you saved and run right over to the Pitti Palace. I liked it better than the Uffizi Gallery and the grounds are fabulous.
I have a few friends working for Caf Tours in Via degli Alfani, they make good deals (38€ for a group guide to Uffizi) and they are super friendly, plus they tell you stuff that recorded guides do not tell you! For example all the intrigues between families in Florence and the personal histories of the painters. So much better than a robotic voice telling you about a painting :)