I still stand by my observations in my write-up/review. However, the differences which I tried to capture in the write-up are really just the strengths and weakness' that are unique to each model. The intent was not to prove one was better than the other.
The biggest difference has got to be the sonic signature of the tweeter(s). The S25 has the Esotar2 which presents slightly more detail and has a hint of more 'air'. The Esotec tweeter in the S3.4 is more forgiving and will make lesser recordings listenable. The second biggest difference is the deeper range [lower hz] capability of the S3.4's.
I honestly think that either model is a BARGAIN at it's retail asking price, as the price-to-performance ratio is among the best I've encountered with any loudspeaker.
It always comes down to your personal taste. The S25 is a more 'refined' sound, more detail, sheer resolution. The S3.4 is a more relaxed sound, fuller range, more forgiving to listen to. The S25 will be more of a test for your electronics; the S3.4 will more listenable on poorer source material without spending a fortune on electronics.
I own both for a simple reason: I couldn't decide which model to part with. I am keeping both pair and rotate them when the urge strikes.