I'm bigger than average, but not Guinness Book. I pass the "dollar bill test": longer than a US dollar laid along the top, and too thick for a dollar to wrap around the shaft and its small ends touch. Make a circle with a dollar to get an idea.
Well, some bottoms have found me a treat, while others thought me a threat, and chickened out when they saw my dick. Obviously they doubted they could accommodate something that big, and I presume a man knows what he can handle comfortably.
So size has been a mixed bag for me. Some guys want it, even used to hit on me in bars because they'd heard the rumors and would come right out and say they wanted me to fuck them, while other guys avoided me over it. And I've had trouble finding guys who can give me a decent blowjob.
So on balance I'd rather be average-sized, a wish that's actually coming true in my 60s, as I've begun to shrink a bit. There's another recent thread here about size, where guys discuss why being smaller can be good, too. I personally prefer a smaller top myself.