I've tried those and wouldn't recommend any of them.
When I've installed CTB I haven't even noticed anything different. ROT starts out with OP Wulfgar with a portrait ripped from one of the novels in Irenicuses dungeon and wants you to go do something that takes you away from the plot of you being kidnapped. I've gotten to an area or two of ROT and it didn't seem to match the main game either either in difficulty. Tortured Souls seemed ok but takes you off to some island and alter's yoshimo's plot / motiviations? It seemed okayish.
FFT the guy seems like one of the most talented mapmakers out there as far as creating brand new areas but his plot and scripts and didn't seem very smooth there would be dialog like this:
"The demon glares at you."
1. So I feel like I should say something to the demon as he sits there and polishes his horn. We are a band of adventurers and want to investigate the temple and don't want any trouble from you. (etc like 3 lines of an answer )
2. Leave.
I haven't really seen much difference when I load Vecna because mostly it's for high level TOB style characters and I don't much care for TOB.
So I guess I'd recommend skipping them all.
