I gotta say...
I like all the scales for collecting,12 inch,sigma,and the 3 3/4.
However i choose only to custom 3 3/4.
I love the 12 inch stuff its really cool and easy to swap stuff around with,i played with these the most as a kid,my older brothers had them all,so who ended up with them,me.
the sigma remind me of superjoes,also played with them,and mego and big jim,loved the wolf pack.
Now as far as the 3 3/4,I collected and played with in my later part of my youth,and they had the biggest impact.
scale really only comes into play when you talk about room to display,I used to try na d put all my stuff out in one room,man it just doesnt work,now i put up a few shelves at a time of different stuff,and i swap it around every now and again,i never get tired of my toy room now.I been selling most everything not 3 3/4,but i still love it all.Comes down to room for me.