Been fighting my SP3 I5 since I got it Sunday as well. Overall it's a nice little setup. The 802.11ac works but dog slow... almost better if I stay with N instead of ac. Pen connects about 1/2 the time. Getting tired of it. Should have waited for the I7 version I preordered. Maybe they'd have had more time and hopefully gotten this straightened out. Thought that by SP3 they would have it down pat....
Will try deleting the driver to see how that goes. If not it's rebuild and back to Bestbuy.