As for me, I only build 1/72 scale models. I've been building WWII subjects for decades now, so I'm pretty used to working at this scale, and I found it quite natural to go on at the same scale with WWI birds. That way all planes are at a constant scale in my showcases. To tell the truth, I didn't think WWI aircraft were so small and I had to look for smaller tweezers and tools.
Regarding the manufacturers, we don't have much choice at this scale, and almost all available kits require a lot of work. They're either very old (Airfix or Revell toolings) or short-run kits (mostly Roden, Eduard, MAC Distribution and former Toko kits now issued by Eastern Express). I understand that we 1/72 builders are a minority in WWI modelling, which means no major kit brand could make profit out of costly tools. As far as I'm concerned, I'm fond of short-run kits for WWII subjects too, so I can deal with that. However, I would surely spare time if Hasegawa or Tamiya WWI birds were available...From what I've experienced so far, I think the best WWI 1/72 kits are the Roden ones. And they're rather cheap.