This may be the newbie tank, but it is no means a place to be spoonfed.
You are probably an educated individual. Its not hard to type the names of these guns into the ASC searchbar on the top right of the screen.
Either of these searchbars will bring up results that will help you with your decision.
There are many reviews for the G&G Mp5SD5 but little to none on this site for the ICS. Google will remedy that for you.