if you dont need emunand (only for eshop access), then you can just stick to 1.2, if you really want emunand for some reason, but dont need eshop access, then go for 2.0b1
in both cases go to the gatewaydownload page and copy the download link of 2.0b2 and replace the file name with either
GW_Release_1.2.zip
or
GW_BETA_RELEASE_2.0b1.zip
keep in mind though, that 2.0b1 has some bugs, sometimes freezing on starting gw mode and sometimes freezing on leaving a game, thus not ssaving properly
to prevent the save issue, start GW mode, enter the game, leave it via HOME -> Exit
if game freezes, repeat procedure, if it doesnt freeze and leaves game properly, then there is no save bug and you can keep playing and saving as long as you dont restart GW mode or shut down console, then you have to repeat the procedure
and always remember to leave every game via HOME --> exit or else gateway might not transfer your save file onto the micro sd card, meaning it wont save