Lil'Wayne

Which portable gaming system should i pick?

i have recently discovered portable emulators, and i have set my mind on getting one, but i am having serious trouble deciphering which is a better buy. the dingoon A320 ( http://www.chinavasion.com/product_info.php/pName/multi-platform-portable-gaming-entertainment-station/ ) or the letcool (http://www.chinavasion.com/product_info.php/pName/letcool-multiplatform-handheld-gaming-entertainment-station/) the dingoo seems to be able to hold more types of games including arcade and neo geo, while the letcool which i dont think can hold those two supposedly has a bigger screen, is the letcool newer?,will it update to getting more systems? please help me

What program do I need to use/unzip/ect a .7z file?

I downloaded a ton of them thinking my dingoo will play the file, but it doesn’t, what do I need to open that file? or what emulator do I need to play it?

Mame4All On dingoo a320?

How do I install it on my dingoo a320? I really need some help with this. Thanks!