best speaker?

If you have the space you might want to add Dunlavy speakers to your list. The company is out-of-business, which makes these remarkable speakers that much more of a bargain on the high-end market.

My system upgrade is going to include getting rid of my 331 and replacing it with a 23.5 or 436 monoblocks and the Revel studio.I am not able to listen to a 23.5 versus the 436 and hence the importance of this forum in giving me a sense of the 23.5/20.6 ML.
Nreddy

The Thiel 36 image beautifully,however I listen to a lot of trio jazz eg Jarret and find them harsh in the high frequency and would like a more open and liquid midrange.
Nreddy

What about other amps viz Plinius/Audio research/Simaudio with the revel studio versus the 23.5?
Nreddy

Well your 331 may not be a problem and I can tell you that the Revels do not have a "liquid" midrange.

If I owned your electronics and had your taste in music and with your complaints about the Thiels, speaker to look at would be

ATC SCM100ASL (has amplifers built in so 331 would compensate for this units additional cost)
Wilson Sophia
Dali Euphonia 4
JMLab Mezzo Utopia/ Nova with YBA amplifier
Wilson Benesch Curve

Speakers Not in any particular order:

The Sophia and the JMLAbs both have a definite sound to them which you may or may not like...a love it hate sort of thing. but they could possibly be what you are looking for.

The others are excellent and are similar somewhat in basic character to the Thiels, the ATC's are the most Dynamic and coherent but the least known, The Dali is not as perfect as the ATC which with the kind of music you like might let it shine in this specific situation. The Curve is a wild card, this one might be the one that works the best with your equipment, hope you have a dealer nearby.

The ATC and Wilson Benesch would be my preferences in your situation.

As a personal aside I have been disappointed with the Revel Studio and Ultima. I have never liked them because of the ridiculously designed crossover (IMO, 1,000 micro farads of capacitance and 60 mH of induction is not a recipe for sonic success) they have between the bass and midrange. The Revel should have an active crossover and not a passive one and the timing problems are evident as the bass seems to lag the midrange. The F30's are a steal I have liked the F series a great deal even though it has a bit of tizz in the highs.

Unfortunately audio companies are afraid that people won't buy powered speakers so they make huge compromises to give the public what they expect.

Hope that helps a little, I hate when I have to turn someones list upside down but speakers in particular are not something you want to buy by the label and none of the speakers you listed seemd to fit closely what you wanted and the equipment you already owned.