I purchased a folio cover/case for my SP4 that had 4.5 stars on amazon. It helps me to use the SP4 on my lap in an airport and i felt it would protect the surface. I also felt it would protect the type cover when I have to stash it in my briefcase while taxiing (have to make the surface look like a tablet so the flight attendants don't make me put it away). Twice now my surface has overheated while in the case. Once while i was home and it was connected to the dock (I think the surface being closed built up heat). The case has felt on the inside where it touches the surface Do others have this problem? Does the surface need to be protected by a folio cover while being stuffed in a briefcase and taken all over the place? I have an SP4 Core I 7 8 gig ram.