Pros: Well made, reasonably priced
Cons: None, really.
I'd absolutely recommend the Belkin car charger/adapter to any iPod owner looking for this type of solution. It's constructed well, and worked exactly as advertised for me. I bought mine with a new 3rd. gen. 40GB iPod and used it frequently - up until someone stole it out of my car.
I was going to buy it again, in fact - but I ended up getting a new car stereo with an iPod interface, so I no longer need it.
The fact that it provides a 1/8" line out jack on the side of it with a volume contol is great though. I used to have an Aiwa car stereo with an "AUX Input" jack on the front of it, and I just ran a cable from it to the Belkin. That way, I got crystal clear sound, tapped right from the iPod's dock connector, and the iPod was powered and charged from my car's lighter plug while using it.
The fact that the Belkin adapter glows green when it has power is a nice touch, too. Helps troubleshoot those little situations where you're not sure if a lighter plug is working right or has a blown fuse.