I did the update via Odin and sure enough it didn't wipe... cool, I just didn't know that
Anyway, re-rooted and enabled SD write access and all is working well for me. Even fixed my missing NFC icon issue
Comms speed is fine for me, overall UX might be a little snappier, though not drastic enough to be sure it isn't just my imagination. Very smooth update on 3 S5's in my house.
Frank W. Zammetti
Author of "Pro iOS and Android Apps for Business"
and "Learn Corona SDK Game Development"
and "Practical Palm Pre webOS Projects"
and "Practical Ext JS Projects with Gears"
and "Practical Dojo Projects"
and "Practical DWR 2 Projects"
and "Practical Ajax Projects with Java Technology"
Creator of the mobile game Engineer (www.etherient.com
For all things me, visit www.zammetti.com