Triode or Ultra-linear? Why?

Several months ago I added PrimaLuna Prologue Mono-block amps and Preamp to my system. Of course, I keep fiddling with the Triode/Ultra-linear switch, It's so easy since it's on the remote. Can't decide which I enjoy most. Leaning toward triode. What's your experience? 


Ultra linear is supposed to have similar linearity to triode, but in my experience, there is no substitute for actual triodes.
lloydc-I heard the Mesa years ago, isn't there an option to run full pentode as well? 

From what I remember, the Mesa is a fine piece, just like their guitar amps.

I have Triode / Ultra Linear mode switches on my MonoBlocks. I like Triode Mode better. Midrange detail is better. I guess it depends on the speakers you are using do to lower power output.
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Very interesting. Most posters seem to enjoy triode mode. Why not just make a superior triode amp, save the cost of switches and additional wiring? Actually, I think I know the answer. Most consumers are impressed by power ratings, nothing else.