I purchase this projector in oct 2011 directly from Aaxa . I be a teacher work in two school and I use this projector nearly every day . I connect my iPhone 4 and ipad 2 to it and also play video file from the internal drive or a flash drive , mostly successfully . the spec be the best in this category at the moment , and the design be good . there be a few detail that other reviewer have not mention , however : \* the fan noise be more than noticeable . it be actually a little annoying . \* the power button be situate such that the p4 can be switch on in a crowded bag pretty easily . \* the button be not very responsive . my feeling be that this be more of a system software issue than a purely hardware issue . button click frequently get no response or a delay response . I feel like the system software be not quite ready for prime-time . \* while it be impressive that they include any sort of internal speaker , it be only usable in a very quiet environment and then really only for speech . there be really no point at all to listen to any sort of music track with it . if you plan on use headphone , then you be fine , but if you need to run a cable to a pair of external speaker then you be lose the cable-free benefit of a battery-powered device . if you do not mind plug it in for power then you might as well get a brighter pico projector . \* the p4 do NOT mount properly on any external computer , and I have try several Mac and Windows machine . the manual say very clearly that it should be able to do this . when connect via usb , it might mount for just a moment , but then it will immediately unmount or produce some kind of error message . I have have absolutely no success transfer file directly from a computer to the p4 . when I contact they support staff about this , I be tell that I should put my file on a flash drive , and then move they from the flash drive to the p4 . this be very disappointing and inconvenient . -lrb- be other user have this problem ? I would like to know . -rrb- \* transfer file from a flash drive involve go into Windows CE , which require the additional purchase of the little usb keyboard . the keyboard be pretty cool , but it be somewhat expensive , and because it be so small , it be awkward to use . \* when copy file , I have frequently have weird anomaly where the p4 seem to think there be two copy of the file , with slightly different directory path , and it give I error message that it be unable to find the second file . irritating ! \* Video playback always start with the first video in you directory , require you to stop playback , go back to you directory listing , and select the file you want . \* although the internal flash drive be 2 gig , the operating system take up a great deal of that , so there be not more than a couple hundred meg onboard , and that be not much room for decent-quality video . I have not try use a sd card . \* the color reproduction , even on a flawless white wall in a dark room , be mediocre at best . there be a few setting to adjust the color , most of which be totally unusable . my expectation be not that high , but I would not want yours to be , either . \* the p4 do not sync as readily via VGA as you would expect . if you cable get jerk out , you can not just plug it back in . you 'll probably have to manually re-sync it or possibly restart the p4 . \* the battery do not last more than 70 minute . none of these issue be substantial enough for I to return the unit or recommend against buy it , but they might matter to you , depend on you plan use . the basic utility of the p4 be massive , although the shortcoming be constantly annoying . I look forward to future unit from Aaxa , where we 'll hopefully get 120 + lumen -lrb- laser drive ? -rrb- from a longer-lasting battery , better and more adjustable color , and perhaps some kind of wireless a\/v streaming . but for now , this be a very handy and useful device .