Is kies 3 the worst thing ever or am I using it wrong?

[AC Question]

I had a galaxy s3. Using kies I could add my entire itunes library then add to my phone. When I plugged in my s5 active it said this version doesn't support this phone, i needed kies 3. Downloaded that and the option to add itunes library is gone. I started adding music files including artwork and all that one at a time, and 80% of them say "unkown" for the artist and don't use the artwork. Is this a massive downgrade in software or am I missing something? Is there a way to add my itunes to my s5 that would be less annoying?