How beneficial is Mobile VoIP over traditional phone calls?

Traditional calls are one-dimensional. They can carry only voice (ignoring the practiclaly de-funct 3G video calls). Mobile VoIP can add layers of information to the call, thus creating a more interesting conversation. For example, photo and location sharing, presence (as Emily wrote in her excellent answer), social network integration, and much more. Yes, cost is much cheaper, especially for international calls. Also, the payment model and method is usually much simpler than your average mobile subscription. For example, Vonage Mobile App (http://j.mp/dlvonmob) enables users to pay by using in-app purchases. (Proper disclosure, I'm part of the app development team).

Mobile VoIP is better than traditional phone calls due to the following reasons: 1) Well, it's mobile. 2) It's cheaper because of the medium of communication. However, since VoIP completely relies on a stable internet connection, users often face issues such as call lags, call drops, echos and so on and so forth. Thus, the quality of calls is highly inconsistent and unreliable in the case of mobile VoIP. To offer the quality of traditional phone calls, and the convenience and cost advantage of VoIP, we've recently launched Ringo (http://www.ringo.co). Ringo is an international calling app that works without the internet! It basically converts international calls to local calls, thus offering lower rates. It's cheaper than local carriers in many countries, and offers some great discounts such as free calling from UK to US. Ringo is currently available in 14 countries. You can read more about Ringo at: http://www.ringo.co

The main benefit to using mobile VoIP is the flexibility that it provides. Another benefit of mobile VoIP over traditional phone calls is that you can see when people are online and therefore ready to speak to you. Cost is of course one of the main advantages and whilst there remains a cost for overseas's calls, peer-to-peer calls are free. For more information on how your business can benefit from VoIP visit --- http://www.btlnet.co.uk/services--solutions/hosted-telephony

In my personal experience, although all responses are completely right on the money and valid, is to avoid high roaming charges. I can even make VoIP calls from Europe for example over a mobile carrier's data network when roaming and charges are much less than making the equivalent overseas mobile call. Of course what I usually do is either purchase a local SIM with data capabilities or prepay a data roaming plan like the one at&t offers (I usually go for the $160 for 800MBPS while roaming).