Let me start by stating the first one I received broke within days of getting it. The spring loaded binding posts are not up to much of a challenge. If you try to put a wire into it that is larger than 18ga. AWG you risk it failing. Mine did fail and considering my 40 years of competent service as an Electrician up to and including Master and Inspector I'd be careful back there! One reason I bought this is the compact size and adherence to a narrow range of inputs. I ONLY want to use USB Thumb Drives and SD Cards. It has input wires for an outside source such as a CD Player but the reason I bought this is for the SD USB connectivity. I cannot review any other standards here. It has hardly any ability to control it's playback. yes you can go forward and back on a numbered system of songs but there is no telling how it arrived at this order. I have a Marine player in my boat for years and knew this would be the case. It is entirely up to you to arrange a setlist and figure out how it would play. This is no IPOD! I love it for it's sound and simple mode of operation, rather than being a detraction it is an attraction for me. One other thing I used as a reason for this purchase is the voltage switch it has on the back so I can take it overseas and play it in my apartment there. I will be packing it in my suitcase along with some nice Polk back channels from a surround system I made obsolete. This unit has limited power but it is tiny and that's part of why I like it. The only drawback to this unit is that it is Made in China. I would gladly pay a bit more for the same thing made by people living in the civilized world but alas this is a decision made by greedy business people I have no control over. I am embarrassed by this low price and understand it reflects the civilized world taking advantage of other less fortunate people. Other than that have at it.