If it is strictly a matter of what I prefer then the answer is simple. Unlimited weight. It outperforms no-weight and limited weight across the board. If you've tried and like 4.0 over 3.2/3.3 then you will probably love unlimited. The biggest advantage aside from performance is you now have ZERO NEED for scales. I.E., Weighing players to pass inspection is no longer necessary. Imagine that! But like ANY method, there are down sides that need to be addressed. And they are the same issues as anything involved with a weighted format requiring limited weight.
Whenever we decide to up the weight from no-weight we make it much more difficult to get more new coaches involved. I'm not saying it doesn't detract from getting potential coaches interested-more interested or less interested. I'm saying it is yet another obstacle/hurdle for them to deal w/just to field a team. Restricted/Limited weight formats (over unlimited weight) makes it even more difficult. Another piece of equipment (scales) they have to have to assure their team's legality.
Don't get me wrong. I prefer weighted over no-weight. 4.0 is good. But the truth is it is no better than 3.6 and only slightly less performing than 5.0-5.5. The real performance in the limited weight category becomes obvious in the ranges of 7.0 minimum to 8-9 maximum. After that it is negligible until you go full blown unlimited. No matter which one chooses, I have found one thing tends to hold consistent. In an unlimited weight format there are no bad bases.
To define "Unlimited", it is using figures of a determined size (length, width, height). Figure weight is NOT important for legality. Materials are restricted to exclude any magnetic, metallic and harmful materials. Bases follow the same line of thought. Bases are weighted w/whatever non-magnetic, non-metallic or non-harmful materials that can be crammed under the shell. Weights can not be visible at field level. I.E., can not hang below the bottom of the base skirt. That is to protect the board from drag marks, etc. This method w/custom figures is my personal favorite way to play.
To make a short reply long....

What I prefer is less important than what is good for the growth of the hobby. If I want to strictly insert my opinions about my preferences and leave it at that, I can play solitaire. That way... it's my way... I can have my way every day. I find that compromising my silly preferences for something that will get many more new coaches involved is the right thing to do for the hobby. That is IF the goal is to actually grow it in meaningful numbers. From there, like anyone else and the rest of us, they can gravitate towards other formats or remain where they started. If the agenda is to get existing coaches on-board plus a few stragglers then do whatever. Doesn't matter that much as most of us say the same thing. "Just tell me what the rules are and if I can make the date(s) I'm game." If you are trying to attract a meaningful number of new coaches to play and stay, the answer is painfully obvious. 3.2/3.3 is it.
Sorry for the long post. Hopefully it is of some use to someone or at least makes them think, agree or not. My cruel master, Prince of Pain, has my number and is calling me. So it's back to the Pratt Cave.....
-Mike Pratt