The simple saying of "If it isn't broke don't fix it" always applies imo. ten different beeks may very well do things 10 different ways.
I myself like going foundationless and with a starter strip. Honestly mostly with the starter strip because I ended up getting numerous boxes of deep foundation for free, so I like to use it, but do not feel the need to use a full sheet of it, so put it on a sheering machine and cut it into 1" or so strips. The bees love it fine, and always draw nice straight comb with it and no problems really. Foundationless is ok also but it does sometimes have a problem with them drawing it out irregular or attaching it to its neighbor periodically. still not a major problem but it is what it is.
using all mediums, for the brood box and the honey supers, makes swapping out boxes and dealing with equipment super easy, and Micheal Bush I believe showed me a study that showed multiple mediums tended to do slightly better than two deeps for instance. I still use Deeps for my brood on some hives and haven't had a issue with them at all, but there is no denying that dealing with two box sizes is more of a hassle than being able to swap out all mediums/etc. I like dealing with mediums a bit more, they are easier to handle imo. I do not use plastic foundation, so cannot compare that.