By far, my favorite neck knife is the little TOPS bar tender... I realized early on I'm not a huge fan of "neck knives" persay. Don't like the swinging feel of anything even a little bit substantial around my neck. The Bartender wears more like a pendant though. Since I always have a more substantial knife on me; be it a clipped pocket knife and/or traditional in my pocket + maybe a fixed blade and/or a SAK Huntsman - sheathed or pocketed... a neck knife just isn't my go-to thing, but having that little "pendant" that double as a bottle opener and triples as just enough of a small, but "extra" sharp edge for those small "extra" tasks, for me is perfect.
#2 choice (for me), in situations where neck wearing is just more practical; having a good sheath on my neck chain to hold my favorite folders, that for me is the best option.... For an actual knife, more then just wearing a pendant, having the blade fold into the handle allows for more blade + handle to be carried in the same size package as your traditional neck knives. Traditional neck knives for me are always lacking in either blade, handle, or just too much weight, or they're just too big in size... So the Bartender I know is super small and insignificant, so I'm not expecting/hoping/asking for much of it in the first place.
But a 4" neck knife is typically what, 1.5" blade with a 2.5" handle or vice versa? 2" & 2"? A 5" neck knife is 5", and still only comes with a 2 or 3 inch handle, or a sub 2" blade...
On the other hand, a 4" folder in a neck sheath is a 3.5" blade inside a 4" handle. Plus, since you can still find 'em light weight to where that weight difference between the 2 is pretty much negligable when I considering the pros & cons, for me it's;
folder in a "neck sheath" > "neck knife" (fixed)
Every time for me...
In a nutshell, if I'm going to have a noticeable weight dangling around my neck anyways, I personally want as much knife in as small a package as I can wear comfortably, and folders allow more overall knife in equally sized packages, at equivalent weights...