I finally got my S5 working -- had to go to a Verizon store and they gave me a new battery and did another full reset AFTER the 4.4.4 OS update.  That helped a LOT, in addition I disabled every preloaded app I don't actively use and that helped a lot more.  I also went to the home-screen settings (hold recent-apps button, then tap "Home screen Settings" and disabled "My Magazine" so it wasn't constantly syncing (what purpose does it have anyway?).

Turned Off / Disabled apps:

• Accessories
• Amazon app suite
• Amazon Kindle
• Amazon MP3
• Appstore (the Amazon one)
• Audible
• BlurbCheckout
• Caller Name ID
• Cloud (the Verizon one)
• Drive (the Google cloud thing)
• FamilyBase Companion
• Flipboard
• Google Play Books
• Google Play Games
• Google Play Movies & TV
• Google Play Newsstand
• Google+
• Hangouts
• IMDb
• Isis Mobile Wallet
• Message+ (the Verizon message app)
• My InfoZone
• NFL Mobile
• Slacker
• Smart Remote
• Verizon Support & Protection
• Verizon Tones
• VZNavigator

A couple apps to avoid -- I use them but they have a significant hit to battery life (1/3 faster drain about) since I loaded them:

• Facebook
• Facebook Messenger
• Skype
• Any VoIP call app