Skype doesn't allow screen sharing or video chat for 3 or more participants without a paid premium plan.
Once you've got that, Skype's screen sharing leaves a bit to be desired. Hangouts allows for screen sharing of individual app windows, which I consistently miss when using Skype.
Additionally, Skype video calls under the premium plan have a fair use policy with a limit of 4 hours per session with a monthly cap of 100 hours total. That may be okay for an individual, but is probably not the best solution for something sitting in a conference room shared across a company.