demo.mojoportal.com has Artisteer 4.1 skins and it works ok on ipad, only problem I see on there right now is they make the search box too big, but it works like they intend for the most part. They do some weird things with javascript to try to make it "responsive", so if it is not working on your site look for script errors in the page.
Also note that when you upgrade to new versions of mojoPortal, if you want the newest versions of the skins then you need to copy them from /Data/skins to /Data/[SiteID]/skins
You might not be using the latest version of Artisteer 4.1 skins, see also the article Important Skin Changes
For phones we use Mobile Kit Pro, I don't recommend using Artisteer skins for phone size screens, see also the article "Supporting Tablets and Phones".