7862 6gb+128gb is nicer for me but currently deen assalam only sell 8gb+128gb and by comparison his price is now same as Momen Tum Beh. Have to wait or 6gb+128gb may no longer produce? Which seller you bought after all?
both TS10 and 7862 is same chipset, but diff motherboard layout. so both firmware is diff and have diff android interface. both also diff sound quality and diff DSP layout.
can say like android smart phone, have same chipset ( eg snapdragon) but is from 2 diff company. ( eg xiaomi, samsung etc ).
as for the screen, also same. when manufacturer built this, they can use diff type of screen, depending on their selling price. much expensive unit might have good screen with QLED, that show sharp and good viewing overall.( eg like teyes ccs3, the price is quite expensive than others, and they are reputable brand) but cheap 1 normally using same chipset, but they put normal screen as to lower the manufacturing cost, so they can sell more cheaper.( eg normal chinese brand,random name, but have same chipset as teyes ccs3, even can mod to fit the teyes ccs3 firmware so the interface is same, but functionally is not same 100% ) .
dont believe anything seller say for the 2K resolution. even the teyes ccs3 only came out with 1280 x 720 QLED +2.5D screen., this is HD only, not even FULL HD.

unless its very reputable brand, you might want to google if the spec is correct. if its just chinese brand, then most likely its marketing gimmick.
i think 6GB should be nice, even 4GB also ok if you dont heavily use ur android player and using few apps at the same time.
i hv heard good feedback on deen assalam and the price he sell quite cheap. last time i did pm him to buy, but since he dont hv stock, i bought from someone else.