riva is a knock off, not the same device,same concept, but made of different materials and products and both put out a lil over 4 vs fully charged both hit at 3.7 under load, and riva is not much cheeper.
rivas have had alot of connection issues with certian attys unlike the ego and not many ppl have had the button sticking, btw 2 totally different buttons. joye will stand behind all their products and is the quality choice. new users need to have options and correct information. some one needs to do a longevity test between the two and see what one craps out over time first, with the same usage. id put my money on an ego.. joye = quality riva = knock off
riva may be cheeper and im not saying something is wrong with riva, plenty of users use rivas, but for me id pick sony over ericison, because quality. so i pick joye over riva.
in eather case do the reaserch and make the best decision for you, not based on what others say.
and btw the megaladon is a modded device, so that is not compare-able here stick to comparing apples to apples