It depends, what OS is your phone using. You might experience stuttering (particularly with Bluetooth playback) with PowerAmp if you are running Android 5.0.0 or higher (I did on both my S5 on 4.4.4 and 5.0.0 and my Note Edge with 5.0.1). I had all of my mp3 (mostly 320kbps) and mpeg-4 AAC files (all were 256kbps VBR) on my 128GB microSD card and PowerAmp didn't quite cut it when it came to Bluetooth audio, that's probably because it started using an ungodly amount of resources.
There's also the standard Google Music app, it works with songs stored on your SD card just fine.
Ive been using poweramp for years with no major problems. The nice thing is you can create playlist with more than 1000 songs. Tons of customization. I currently use a sandisk 64gb micro sd card with over 6000 songs loaded to it, as well as 6 different play list from google play all access music.
Also if you do run into problems with poweramp the developers are very responsive and helpful.
My fiance was with her S5 and now Note 4. But that wasn't until after Verizon pushed out updates to them too. I tried following what people were saying on the PowerAmp discussions (increasing cache size, increasing allowable resources, etc.) but it still skipped like crazy whether we were using Bluetooth or a wired connection (Bluetooth was far worse).
I disagree. I have tried to get help on multiple occasions (I'm up to over a dozen now) and I have never heard back from the developers except for a single time where they sent me to the steps for increasing the amount of resources that PowerAmp could use. I responded saying none of that worked and they never got back to me. That's after I purchased PowerAmp which was initially great on my S5 and Note Edge. I'm more inclined to believe that there is something wrong with PowerAmp and Android 4.4.4+ on Samsung devices (which have had wonky Bluetooth, Verizon has even released a patch specifically for that and it still didn't fix much). I have another friend with a One M9 running Android 5.0.1 (I think) and no issues. My Mom has an LG G3 with 5.0.1 (or maybe even 5.0.2) and again, no issues with PowerAmp.
I just can't recommend it for the Note Edge if you are running Android 5.0.1 through Verizon. It might be different for other carriers but it is nothing but problematic on my Note Edge whether I'm using Bluetooth audio or wired.