Better for what application?
7 al 3 has all the bells and whistles..If it is a race car(drag racing) and you elect to use the 6al, and you want to use an electric shifter, a two step for the leave etc...then you will have to buy the 6AL Box,+ two step+ rpm switch+ whatever else you decide you need...the cost of all that mumbo jumbo will add up fast. With the 7AL-3 you already have all that crap built into the box...not to mention built in start retard ....much easier and probably cheaper.Definitely more simple wire up..It's a Pretty cool box .A friend of mine had some trouble with his but you will get that with any product I suppose....If it is a street car only with moderate compression the 6AL is a good box.