Firstly it's probably worth a few minutes about me and my preferences, this will probably add some context. I have 'preferences' and priorities that don't match everyones, but are somewhat consistent with my group of friends who have hifi systems. I am looking for life like scale and weight, emotion, PRAT and musicality (before anyone talked about this to be honest), tonal richness and tonal colour. 'Accuracy' is quite a way down my list. I say this as I cannot remember 100% everything about the comparison.
The system at the time was Linn Sondek, Syrinx PU2, Koetsu Red, Audio Innovations S800 transformer, Croft Mirco preamp, Quad II power amps. It's worth noting that some of the items listed above might seem perhaps compromising, but I had tried and settled on this set up after a number of alternative amps (Audio Research SP10 MkII, early SET's, Leak's, and even Krell). I expected to dismiss the quad's quite quickly but with selected components they were extremely good and had tonal density and richness without compromising speed, dynamics and 'bite'.
Anyway moving on to the S2's. When I had the horns, they were easily persuaded to sound like a cheap PA system if they weren't fed with sympathetic sounds and this provoked the arrival of lots of stuff to experiment with and this included the S2's. I was moving on from Magneplanar's fed by Robertson 4010 amp (chosen in preference to a Krell KSA50 amongst others) and the voices and layering was for me very good with this set up (but compromised with scale, weight and ultimately dynamics) 'Memory Motel' by the Stones was awesome with the maggies !
Right S2's, well they came, they were heavy and this was late 92. I cannot remember explicitly but the S2's were more 'polite' then the S5's. The 'bite' and 'balls' on some of the jazz saxophone's was not conveyed with the same power from memory. Tonally I think (Not 100% sure here) the S2's were a little darker (something I usually like) but seemed a little more reserved and less dynamic. I do recall listening to a superb album by Wilber Du Parry 'that's a plenty' and the 'body', scale and sheer 'being there' was lost a little with the S2's. I did listen loud, especially after a few glasses of wine...
Another track by Sidney Bechet showed the same, you had to duck from the trumpets (in a good way) with the S5's, somehow there was a little restrain with the S2's. I could have happily lived with either, I did however feel the S5 was a little more dynamic, emotive and also a little 'thicker' in texture. By this I mean say brass instruments had weight, colour and 'edge' it was like a 'thicker' slice of cake, just as clear cut, more body and energy included in each slice. The S5's are a bit uneven from memory, but that's like the mid hump of early Linn's not accurate but I like it and maybe this inaccuracy pleased me a the time. If I wanted to pop a disc on like Natalie Merchant and want her to really live and breath her emotions it was the S5 over the S2 for me at that time with my system.