The front end was changed to Decca design mic preamps - (now where have we heard that phrase before?)
Sir Mick Hinton mentioned the change.
I've used one since around 1989, and now use it with DAV BG1 mic preamps for summing, occasionally adding Audient preamps and Amek/Neve 9098. I have a Sadie LRX, but always seem to end up taking out the mixer. I like recording with it, and find it so easy to work with, it's been uber reliable. Everything is recorded analogue right up to the point where it is converted for storage.
dda undervalued?! - depends a bit on series i'd say and possibly also who you ask...
[i admit that the somewhat convoluted course of history regarding dda's court case (with soundcraft?), partnership with ev/dynacord, integration into klark/midas, later development leading to audient) did not only confuse me but has led, if not to a reputational damage, at least to a certain degree of uncertainty, especially among those who had invested in the brand on a large scale...]
i've used desks from pretty much any era and in various applications; i don't recall details of every series though but i loved the (dda-designed, midas-branded) xl200 at the time (which i later sold though); funny enough, i actually happen to still have a dda forum II somewhere in the warehouse (and possibly also a smaller desk from the 'interface' series...- or was it a cs-3?)!]
To the topic of DDA / Audient, their top of the line console includes an output section by Chicagoan John Hardy--990 op amp output for extra sonic joy.