if you are still weighing the pros and cons, I put another vote for 8x10 or 7x9.5. I just bought the most affordable basics, a russian wooden camera, some barrel lenses, a shutter and one shuttered wide angle lens with slight scratches. all this wasn't 500$ yet. I only have 2 double holders, but I'm looking for more if I see a bargain. it's real fun already. and it's so different from smaller formats.
I mainly shoot 120 film. when most professionals moved to digital and their old gear became out of fashion, I bought myself a 4x5 technikardan. it was great to explore it, but enlargers are really really expensive. and in the end, most of my prints are 7x9.5 or 8x10. so the difference between a 120 and a 4x5 negative isn't that impressing at this size.
all I can say is that a direct print from 7x9.5 has something special, maybe it's not rational even, but I just adore it. this is my very personal opinion of course. I just wanted to let you know.