How far have ss amps really come in the last twenty years?


I have owned and enjoyed my Jeff Rowland model 8 ( recently modded and upgraded by Jeff to the last version) for many years. I recently had the opportunity of comparing it ( after mods) to a few of the current ss models from Gamut, D'Agostino, YBA, Parasound, Sim audio, CH precision, Constellation,PS audio,Pass Labs  and Musical Fidelity. The results were very interesting, because to my ears and in the systems that we did the comparison, the Rowland held its own against all but the most expensive D'Ag and CH amps. Even those were only very slightly outclassing the Rowland in the areas of top end resolution...and a tad in the bottom end resolution. Now the thing is that the last revision to the Rowland 8 was designed by Jeff over ten years ago! 
So, my question for those more technically inclined than myself is...how far has the design of ss amps come in the last ten...or even twenty years? 
128x128daveyf
In an interview with Steve Guttenberg Dan D'Agostino commented that one of the best sounding amps he ever produced was the KSA 50. I have a KSA 300S and I have wondered how it would compare to today's high end SS amps. I have personally heard a direct comparison between Bryston 28B3 monos and 2 different high end Class D amps which shall go unnamed. The difference was striking and obvious within the first 5 seconds. The Brystons incorporating a traditional design were far superior in every respect to the more "modern" Class D amps. So, addressing the original question, it's clear to me that newer circuit designs are not necessarily better. 
roberjerman,

Please give us a list of all of your equipment. Also your age would be nice. I am seeing a distinct pattern.
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The OP and some others are missing the most important consideration of amplifier design here.  Namely, that good, well thought out design techniques have been known since the mid sixties.  That is a long time, even for a senior like me.  What has changed is the advent of more available and more affordable high quality parts to choose from.  So, it is easier ( and cheaper in inflation adjusted terms ) to make high quality amps than it used to be, but none of that matters if your intent is to "design to market"  instead of producing the best equipment you can for a given amount of dollars.  This difference is closely comparable to the difference between GM and Toyota in auto manufacturing.  One tries to make the most profit for a given class of cars, while the other tries to make the best car they can at a given price point and still make money.  The same issues are true in audio manufacturing and always will be.  The other side of this "human" issue can also, be compared to autos.  For example, those people who feel the need to spend more than others can in order to say that they have "the best" of whatever.  No one needs to spend $150K+ for the highest quality auto and no one needs to spend $150K+ for the best audio gear either --BUT SOME DO.