Pros: very light sturdy crashproof software (can anything better be said?) works
Cons: Sound volume could be a problem is you are real hard of hearing.

We travel to New Zealand frequently and because of the cost involved in making international phone calls from New Zealand (a la Telecom), something less expensive is a must. We initially installed Skype and used a headset. However carrying a headset and your laptop as you travel adds more bulk to your carry-on luggage and a headset takes up additional space and is a nuisance to put on and off. We purchased US Robotics 9601 and 9602 USB wired phones (one for each laptop) from Walmart - about $30.

My 2 year experience is as follows:

very light
sturdy
crashproof software (can anything better be said?)
works


Simple, works. We have used these everywhere we have been able to get a wireless or wired signal. Last year we purchased a local Skype number in the USA. Phone attached to laptop rings every time someone calls that number no matter where in the world we are. Voicemail if the laptop is off.