I use and have used a wide number of aftermarket handles on my Stellas, and really prefer them over the original Knobs...
My favourite were the original Tuna Max knobs for the FA series.... unfortunately they changed the shape/design a little on the new ones for the SW series which are still great, but not as great as the originals in my opinion...
The FISHERMAN knobs are incredible, but silly price ( like most FISHERMAN products )... they really are fantastic though...
Recently fitted the JM Knobs to a couple of my reels and was really impressed... these are as close to the original Tuna Max Handles in feel and comfort, and perfromed fantastically... available in a super wide range of colours too, and readily available which is great....
I've got a Charcoal/Gun Metal Tuna Max Knob for a 18000SW which is brand new... fitted to my 18K, but never used, replace it with a JM.... if anyone wants it, PM me, I'm sure we can work out a plan... I won't be using it, so would rather it goes to a good home and gets fished...