The author for SkyUI version 4.1 hasn't updated it for about 2 years (from the SkyUI Nexus page: Current Version: 4.1 LAST UPDATE ON JUNE 24th 2013), was something about it was to complex to sort out the Alchemy/Smithing menu's (can't recall exactly and can't seem to find it at Nexus again). Then this "pay for mod" come on workshop and suddenly there is a SkyUI 5.0 coming up in the matter of a couple months. Seemed that they also got contacted by Valve about this but didn't put up their mod from the start.
Would be intersting to see if SkyUI 5.0 will be uploaded to Nexus now or not though. Although 4.1 works just fine and the Alchemy/Smithing menus is not that troublesome..