Here are the main issues hard to solve with Skype but easily handled with HipChat.

Pickle #1. Group chatting Pickle #2. Offline mode Pickle #3. Sending pictures Pickle #4. Code snippets Pickle #5. Link search

And of course integrations.

We've gathered all our thoughts in an article - http://weavora.com/blog/2014/02/04/why-we-love-hipchat/