I had pretty much decided to pass on sp4, given all the trouble sp3 has given me (3 replacements, countless disk wipes).
but if the following rumors are true, I may reconsider:
* 16G memory and 1T disk
* faster chip without crazy spinning fan (note: does NOT have to be fanless to be an improvement)
* bezel-less 13"ish screen on existing chassis in desktop mode
* when flipped to portrait mode, simulated bezel where edges of the screen stay dark except for "soft" windows button at the bottom (switches based on your orientation)
* thinner (can just have a shim to make it fit in current Dock, or hold it toward you when docking)
* "keyboard dock" that makes it truly lappable and adds most of the ports you get with normal dock, yet not so bulky/heavy.