I own and use both, it all depends on which rods I take, what the weather is like, and if it's day or night. Normally I have a multiplier and fixed spool for each rod I take, and use the multi during the day light, and change to fixed when it's getting dark, but if I have the sea streak with me, I don't get as many birdsnests, so feel comfortable using it at night, and will have one of each going.
How I get on with my latest auction wins I don't know, but next time out I will have 2 Penn 85 and a 78 with me along with 2 baitrunners and a heavy fixed spool. Chances are, I will use a multi and fixed, one on each rod in the tripod, and try some close in scratching with a multi or even try a bit of lure with an old boat rod I have.
As for distance, I don't think it makes any difference to me, as I don't need to get to far out around here, and I fluff it to many times to be consistant :whistling Long distant casting may look and sound great, but if the fish are 20' out, why put the bait 100yd out?
I used multipliers for years but changed back to fixed spools a couple of years back as I wanted the flexibility of extra spools with different breaking strains without having to carry loads of reels. With the build quality of modern fixed spools being light years ahead of the clunky efforts of years ago, there really is very little to choose between the two these days so I'm happy with my choice. I also don't miss the wrist ache of winding in over a hundred yards of line on those piffling, tiny little 7HT handles!
ive used multi's for nearly 40 years. just recently though i bought a myself a large fixed spool. the idea being to use braid with higher breaking strains and lower diameters, to give me some distance on marks that would need a mono that would actually restrict distance and also less tide pull on some of the marks i fish [if you know what i mean].
i,m confident with and enjoy using multis so will still use them when conditions suit.
lots of people locally are now using fixed spool reels for most of there shore work. they are also swithing to braid on them looking for increased distance.
as a continental , i started and fished with fixed spools for more than 30 years and was very happy with them : as said , modern f/s reels are really good and you can cast as far as any multiplier with them , the retrieve is faster , and you don't have to thumb the line on the spool .... but about 5 years ago i tried a multiplier for the first time and liked it so much i hardly ever touched my fixed spools since , my 2 boys use them now !
Fixed spools cast better if they are fully filled with good soft line, tried lots of makes over the years but Ultegras are my choice now, the old XT take some beating as built like tanks, I bought 3 cheap on the bay for around £60 each, line lay is very good,