I had an Orvis BBS IV reel. This reel was made in England, and the owner's manual is different than the MIC BBS reels. It was supposed to be a 6-8wt
reel, and held about a zillion feet of backing with a 6wt line. That adds weight, and all of that backing takes time to dry if the reel gets dunked (you
have to meet my wife: she's a champion reel dunker!). The nice thing about the large arbor is that you don't have to carry a ton of backing, but still get
the benefit of larger coils. I just spooled up a reel with backing, and it seems
that if I ever have a fish take 90 feet of 5wt fly line, and a little over 100 yards of backing, he deserves his freedom. Tarpon and bonefish are excluded
from this grant of freedom, however, and I'd load those reels to the max.
Soooo.....You can buy the SA reel, and load it up with lots of backing (or not), or buy the LA reel, and load a resonable amount of backing for a 5wt. I use larger sized mid-arbor reels for the most part, and line memory is now.....well.....just a memory.
I did use a standard arbor 3 inch reel last year briefly,
and reeling in 40 feet of line seemed to take so much longer than what I had become accustomed to.