[AC Question]

Let me start by saying I have owned an android powered phone before, the original Droid from Motorola. While that phone was a huge improvement over what I was using before (flip phones) I did experience a lot of strange occurrences. I had apps freeze quite a bit, as well as the Android OS itself. I found myself having to take the battery out and reboot the phone at least 2 times a week. The next phone I got was the iPhone 4. The experience was night and day different. I never experienced app freezing, or OS problems with Apple. It was so much more refined and just plain worked better. Now to my current reasoning for considering going back to Android -

I am a huge music fan, and currently have to carry two devices, my iPhone, and iPod. I have so much music that it wouldn't fit on even the largest capacity iPhone. I have read the rumors that say Apple may release an iPhone 6 that has 128 GB capacity, but my thing is, it will be incredibly costly and I'm not willing to continue to purchase the most expensive phone in the Apple lineup just to have my two device issue resolved.

My plan is/was to get an S5, then buy a 128 GB SD card. This way even if I upgrade to the next Galaxy phone a couple years from now, I can still get the base storage phone, and keep my SD card. Now to my concerns -

1. Does Android OS phones still carry the issues I experienced back in the day with freezing apps and OS? I'm hoping over the years this has been eliminated.
2. How is the native music management on the S5? I love that my iPod organizes my music in a structure. I can navigate by album, or by artist to find what I'm looking for in a massive library. Is this true on the S5 as well? I still have all my music in .mp3 format so no worries about converting from the iTunes files.
3. Are there any issues with housing my music on an SD card as mentioned? Music doesn't HAVE to be stored on the internal memory right?
4. Any other things I'm not thinking of that I will lose when moving from Apple to Android would be appreciated.

Just trying to make an informed decision. Thanks guys!