psneeld
Guru
Can't help much there. I have enough of both that I don't buy sockets anymore except for true oddball situations.
I'll just point out, to me anyways, that one size fits all usually have a big screwup factor somewhere. Some fasteners they will fit well and some not so well. Some metric and inch sizes are dimensionally so close they are interchangeable. Some though, although they may fit, they may damage the fastener if it is tight. Often are good in light duty situations but if you really have to pull hard on the wrench/socket then they can ruin a fastener.
Often a really tight hex head fastener can only be dealt with a six point tool. The 12 points although more universally applicable will ruin the head particularily with smaller fasteners.
I've looked at those sort of semi spline sockets but haven't tried them. I'm sure they would be a good way to keep the tool count down but just be aware that there will be some fasteners they may damage if tight.
If you go that route buy good quality tools and be aware of the limitations.
I bought a set for my son for Christmas...at Lowes on sale so I don't think they were moving well...but the set actually suggested they work well on damaged fasteners.
I told him if they didn't work...then I'd swap a new "normal" set with him.