Issue Syncing Music to iPhone

I'm posting in this forum because after searching off and on since the iPhone 6 released, I haven't been able to find a fix and I know I'm one of many who are experiencing this issue. I purchased my iPhone 6 (128GB, Verizon) on launch day and since then I've had the same issue syncing my music to my iPhone from iTunes on my PC (first iTunes 11, now iTunes 12). I always keep my devices and iTunes up to date, so I know that is not the issue.

The issue is, when I try to sync my music to my phone (I have roughly 50GB of music) it will sync most of it, but not all. When I check my phone, some of the music is there and some is missing artwork that should be there. When I try to resync, it gets stuck on the last step and either takes music off or continues to show the music, but if I try and play a song it'll skip to the next working song. Syncing a second time DOES NOT WORK. I've tried restoring my phone, and that works for the first sync. But if I try to sync it again some other time when I've added more music to my library it removes some of the music once again. This is extremely annoying because not only do I have to either restore my phone or clear all music through General > Usage but I have to also wait half an hour for all of my music to sync. And even when I get it all to sync, I can't add anymore music except for music purchased directly on the iPhone.

I'm pretty sure there isn't a fix for this, but have any of you guys found something that worked for you? When will Apple fix this issue?