I didnt find any stock file manager app, recommending ES file manager. quite easy to use and free.

Thanks bro, but im really confuse     which one i will give up both of them are really nice gadget

camera: HTC one having only 4mp (ultra pixel) camera, S4 having 13mp? in term of pixel, obviously S4 win miles ahead.. imo camera pixel is where i think HO is lacking the most, in which in most if not all smartphone nowadays 5mp is very common and considered low end dy.. but, so far, for daily usage, i think HO camera has done well to serve my needs, and taking picture in low light condition is better now (in which before this, i just don't have appetite to snap picture in low light conditon while using my previous phone).. HTC Zoe is a bonus, its fun to use, there were just some times/condition that i think Zoe is really practical to use..

in terms of design, HO having premium aesthetic while S4......... (plastic).... but depends, sometime ppl consider more on performance than design.. 

but, really, both are major flagship as of today, why not give it a try on both before you decide.. you are asking in HTC One thread, of course recommendation more bias toward HO.