I'm from the US, and am traveling to Panama. I would like to rent a car in PC, but am looking for advice about which companies are good, any success stories or disasters, cheap prices, etc. Also, the LP guidebook doesn't say anything (that I could find) about driver's license requirements. Know anything about that? Also, what are the general driving conditions in the country? Crazy driving like I've experienced in Peru, or slightly tamer? Much appreciated!

your us license will be honored in panama however the streets are a zoo.i don't know about peru,but i'd compare
panama with india as far as driving is concerned.cabs in panama city are every where and cheap,as is bus
transportation.

If you aren't going out of the city, then don't bother renting a car - just use taxis as they are super cheap - $1 to $1.50 anywhere in the center area of the city.
Driving is nearly as bad as Peru and the streets are not in any regular grid so finding your way around is a nightmare - no street signs or street names.
If you do want to explore out of town then go ahead - all the major brands are here and they are all about the same, although we've always had good service with Thrifty as we have a corporate account with them.
Cheers,
Andrew