Aaron is looking for an alternative to Skype for voice over IP (VOIP) calling. Is Google Hangouts a good idea? Leo says that Hangouts is a good option, but Google hasn't been giving it much attention to it as of late and may kill it. Aaron can look into Viber, Tango, Line, and even Facebook Messenger. Aaron should remember that anything he uses will require everyone else to use that service as well.
A more sophisticated option is Linphone. It's a SIP program that would allow him do to a lot more than Skype and make VOIP calls and group chats. It works quite well and the sound quality is up there with the best.