when i was young the 308 was the reel , but they were hard to come by and a little light for some of the larger species i liked to fish for back then . line capacity was a worry as i fished a lot for real big carp as a kiddo and a big carp can flat peel line off a reel on the hook up .
and to be sure just being able to buy one reel a year was a blessing ,so i mostly always got a 300 ,i did own a 308 for a while though when i got older and could afford to have 2 reels ....