I have never auditioned CS2.7, but I did that for CS3.7 - when my choice was between CS6 and CS3.7. I think mid-high ranges are
comparable in both speakers, perhaps CS3.7 give wider and more intensive mid-high ranges, although low frequencies are not comparable - CS3.7s lack them, whereas CS6s give deep solid natural bass. I do not regret that I have chosen CS6s (the coaxes needed reparation that was done in Thiel by Rob Gillum quite well).
I also own CS3.6s and MCS1s with Thiel smart sub for more than 10 years already, which I also like. Before MCS1s I had some time CS1.9 that have decent high frequencies but I think their mid ranges are a bit saturated, nothing to say about low frequencies. Bookshelf MSC1s are uncomparable superior to CS1.9 s.
I would not hesitate to choose CS6, although if you have a small room and your amp gives below 100 watts then perhaps CS3.7 would be a better choice.
comparable in both speakers, perhaps CS3.7 give wider and more intensive mid-high ranges, although low frequencies are not comparable - CS3.7s lack them, whereas CS6s give deep solid natural bass. I do not regret that I have chosen CS6s (the coaxes needed reparation that was done in Thiel by Rob Gillum quite well).
I also own CS3.6s and MCS1s with Thiel smart sub for more than 10 years already, which I also like. Before MCS1s I had some time CS1.9 that have decent high frequencies but I think their mid ranges are a bit saturated, nothing to say about low frequencies. Bookshelf MSC1s are uncomparable superior to CS1.9 s.
I would not hesitate to choose CS6, although if you have a small room and your amp gives below 100 watts then perhaps CS3.7 would be a better choice.