Lets talk stall converters

Icetech said
Pulled the trans and swapped the converter yesterday... car drives like a car should now.. Not sure if i will send the FTI back for repair or trash it.. depends on cost and if i could resell it to make some of the money back

What does the new converter do (or what does it not do) that shows improvement over the FTI?

Articulating it will help future converter buyers to understand why the correct converter is worth the money.