I'm honestly not sure which mode I'm using. My keyer has 10 "emulation modes", three of which have an "A" in the description. None of them mention anything about "B". (it's a kit-built CMOS-4 from idiom press) If I had to guess, Id say I'm running "A" mode.
I like to use iambic wherever I can. I've heard folks say that they don't like it. I've read long treatises explaining how iambic is actually slower than slap keying, and all the world speed champions eschew iambic mode. That's all well and good. I just think it's fun.
I also use the forced letter space timing on the keyer. I really like that feature.
All that being said, I still use my old bug more than I do my paddles. Once again, it's fun. kinda like playing a banjo