Shave Number 4 about to happen!

Hello everyone! I have been very lucky so far. I haven't cut myself yet.
I don't understand the big deal about the different razors. I just want a good shave! Why are the larger razors worth Sooooo much more? I somewhat understand about the shape of the razor. Why is the Filharmonica razor cost so much?
Does the larger size make for an easier shave? Why are some razors favored over others price wise? I figure most of the German/English/American razors are made with similar steel and should hold an edge about the same amount of time. Am I incorrect?

Valuation is a wonky thing (one of the reasons why we don't get into that in the forum here!) and appears to go in waves. At one time, Filarmonicas will be the hot ticket, now it appears to be W&B Barbers Use. (which, incidentally, really sucks for me as I'd quite like one, but am not going to pay a fortune for the privilege!). I understand Dubl Ducks have had their turn, and if only I knew which maker/style would be next on the gravy train, I'd be stocking up! :)

There is quite a bit of difference in the steel, in the grind, in the weight of the razors. All of these will contribute to a very different feel when shaving, so from a USER's point of view (as opposed to a collector) there can be rational explanations for preferences. I assume collectors like what they like just because they like them. I like what I like because it works well for me. Personally I like big old Sheffield choppers because for me, my face, and my beard, they just work better than any others I have tried. Others, having tried the same bunch of blades, may well conclude that a little 4/8 Helljestrand or a 6/8 full hollow something else is right for them.

Good luck with #4!