I am right between sizes on the LHT and I would like to get advice on what the best compromise is. I am 5'7" and am long in the torso. I can barely stand over the 50cm size frame - I can only lift the front wheel about a cm without jamming the top tube into my junk. When I'm on the bike, it is otherwise very comfortable. On the 46cm frame, I can comfortably stand over the bike, and lift the front wheel an inch or more. When I'm on the bike, it feels shorter, but that may be a matter of setup.

I will be using the bike for commuting (12 mi round trip, 3-4 days a week) and weekend rides / light touring. I generally like a more upright position.

What are the main trade offs in going to a larger size? There is virtually no difference in wheelbases between the two sizes.