Here is an interesting article on Cnet. Microsoft is aware of the issues people are having and they working hard at fixing it. they blame the transition from a P2P service to being Cloud based

http://news.cnet.com/8301-1035_3-576...medium=twitter


Why has Skype been a problem child? Microsoft pinned the blame on the service's transition from peer-to-peer networks to cloud-powered servers. Designed for desktop PCs, Skype has been slow to adapt to a new world where people juggle multiple devices.
"It's not that we've been trying our best to be amazing at chat for 10 years and sucking at it, it's that we've been doing a great job doing what we were born to do and now people want more out of us and we're making the investments to expand and be great at that too," Kunins said. "We're not there yet, but we will be."