Retired the Stradic 4000FG
So I went to try a few replacements.
At first I purchased an Ultegra 4000FA on a closeout. Current model is FC, so it's been a few years since the FB version came and went away too. Current retail is $169, so up from the old $149 when I purchased. Anyway the reel is very smooth as should any brand new reel is. After the first few catfishing trips and even on the first one. I could feel the reel struggling with big fish on. I had to pull with rod, then ease up and reel up. In a way it sort of reminded me still of the cheap reels I use to buy and needing to put a lot of effort into with big fish on.
I finally purchased a Stradic 5000FL. The nomenclature is STC5000XGFL. C for refering to being compact as it's a slightly larger spool on the same 4000 reel body. XG for the slightly higher gear ratio of 6.2 to 1 vs the normal on at 6.0 to 1 gear ratio. So it's been years since I had to replace the Stradics. Going from G, H, I, J, K, to L. It's been like over 20 years or so.
The Stradic 5000FL current retail is $239 and up $20 from when I bought mine. So for fishing it did so much better in comparison to the Ultegra 4000. There is more winching power on this reel for sure. There is less noticeable flex in the reel body under load as well. The 5000 also has a non folding handle. It is a straight one piece.
I also bought a Twin Power 5000FD. Current retail is $459.99, significantly up from original price. Like the Stradic 5000FL, it's nomenclature is TPC5000XGFD. The Twin Power is the Japanese market equivalent for the Sustain reel in the US. However when the Twin Power came over in to US market, it had become so much more than a Sustain reel and position itself above a Sustain. This current FD model is the only reel that Shimano produces with a Titanium Nitride spool lip. It was what used to be on the older Sustain models that separates it from it's duplicate Stradic.
When hooked up with big fish, the Twin Power really lives up to it's name. It really has so much more smoother winching power over that of the Stradic equivalent. Both reels are rated to 24# of drag. The Twin Power is just slightly lighter in weight at 9.2 oz vs 10.4 oz for the Stradic. A lot of that has to do with the handle and knobs. Probably a lighter rotor and spool on the Twin Power as well. If I compare the Twin Power to my old Stella 4000FA, the current Twin Power 5000FD is smoother.