Need a new Screensharing tool

As I'm sure many of you do, we totally rely on audio chat and screensharing to enable our remote working. Skype has been our default tool since around 2009 but it's now starting to get a little too unreliable - cutting out/poor quality video etc. Has anyone had success with any other tools that they could please recommend? It's purely pair programming although sometimes we do invite other people onto the calls...