So, after some playing around with the Adafruit FX board, SERIAL MP3 PLAYER V1.0 from CATALEX, and The Citrix EZMP3
The FX is great, but limited in space...cause I want to put more songs on it than I should. I also used the version with a headphone out and no amp; the sound volume was lacking for sure.
The MP3 player from Catalex is cheap and has loud volume, but it picked up a lot of distortion and had pops when tracks ended.Some crazy programming with timers is required for looping. I dont know if it has an "Amp", but it is louder than an FX board that doesnt have an amp.
The citrix EZMP3 shield has good sound, good volume because of the 3W amp, but only plays MP3 and Wav files. There is a pop after a wav file stops playing and a gap when one MP3 stops and another starts. I haven't been able to remedy this, but its not too noticeable.