I have two old ABU 506s in good shape and after using them for some time I'm not convinced but keep using them all the same.
They are not for big fish (lack of power and smooth drag). Besides, the bedding in and the slow retrieve speed is a bit of a problem. I once had the problem of the spool coming loose (in a match, now there's a trauma) but this might be just me, also being a 'closed face novice'.
I cannot find what it brings to the table, apart from opening the 'bail' and taking up slack without using the left hand. Not a priority since I gave up smoking years ago. Even when trotting there's nothing I cannot do with my other reels. Closed face reels where very popular years ago, fishing for zander in deep water with live bait under a float. Taking up slack was the USP back then as well.
However, they look stylish on a float rod
. That might be the reason why I use them. Just like I'm fond of the old ABU's and Mitchells on a glass rod, when spinning for pike. With a decent Ondex spinner and Nylon all the way. Not neccesarily the best but most certainly feeling classy
.