Having a travel charger is important - you don't want to get to a point when your battery dies during an important meeting.
Whether you use a car charger, an AC adaptor or a battery pack, all will help you keep running. At $13.50 with free shipping ($20.50 for Edge version), this product is great and it's cheaper than many other similar products.
I used the two Visorsolutions products, along with the Handspring Travel Charger, to give me battery power, DC power (from the car) and AC. Everything worked well and wherever I went I was prepared for the worst.
Overall (not an average)
Annoying to have to remove and replug AC power supply from cradle.