This question keep coming back! and the worst is that I only started recently shooting 4x5!! Well I am not completely new to sheet film as I started by shooting 3,25x4,25, a format that I really appreciate.
When I was shooting 3,25x4,25, I was always dreaming of 4x5, thinking that it would be bigger, better, nicer etc... but now that I have it, I wonder if for all the effort it takes to make a shot why shouldn't it be done on an 8x10 and enjoy all the benefits of the bigger format?

I see several advantages (for me at least) :
- larger neg, more info recorded, possibility to print large if desired or contact print
- better rendering of volumes and tones in general, good for architecture photography (what I do)
- slower operating mode, make me think more (never hurts
- 2 film holders in the backpack, 4 photos per session - good enough for me

One disadvantage that is keeping me away: price!! for everything!! 8x10 kit for my Arca Swiss camera, lenses, film holders, films... Well I can still work on my 4x5', get better and better so the day I ll take the plunge I ll be ready...

My thoughts..