I have hunted with a 64" recurve, 66" longbow and currently have a 68" longbow.
Funny thing with the 68"er is I thought I was getting a 66" bow to try. I never would have ordered a bow that long. When it came, I just strung it up and went outside to shoot it a few times. I liked it immediately. I did not realize it was 68".
Currently my favorite bow is a 60" Blacktail, I just shoot it better than anything else. But, I wish it was at least a 62".
I can only remember one time where the length of a bow was a hindrance. I was in a treestand that was placed in a tree with three trunks and even then it was awkward with my 60" bow.
When you really measure bows side by side, like Charlie said the difference between a 60" and a 66" is only 3" on each end. Not much in the real world to worry about.