OK Ive established from this thread and others that DxO is a dirty word on this forum.
Not so at all, it's far more nuanced than that.
DXO "scores" should be ignored. DXO scoring is weighted, and how they weight (especially for lenses) is difficult to discern or else completely unknown. It seems rather clear that they have certain brand affinities and brand aversions. DXO seems very averse to Canon, despite the fact that, as you say, their lens measures clearly show that Canon lenses perform exceptionally well and should technically "score" higher.
The general rule of thumb with DXO is to simply ignore the scores, and read the measurements. There is still some danger in that, however, as not all their measurements are actually measured. Many are derived mathematically from actual measures, which implies a certain amount of assumption goes into many of DXO's measurements...an assumption of ideal behavior (which, for anyone familiar with reality, is rarely ever ideal.)
Last, beware that DXO has been known to change their scoring mechanisms behind the scenes without being clear why, when, or how...so sometimes information changes without prior disclosure, and god only knows why.
DXO information needs to be taken with a healthy dose of salt. It isn't always reliable.
The consensus (i.e. JRista and Neuro -- does any other opinion really matter on this topic?
) is that their measurements
of sensors are often accurate, but they then apply arbitrary weightings
to get a final score. Their lens measurements have been not so great.
There seems to be general consensus that DXO's software is excellent.
My question then is its easy to find fault but what alternatives for measurement are the experts on this site putting forwards?
For measurements you certainly can look at DXO: just make sure you understand their methods so you can place them in context. If you're looking for a simple score to rank equipment, I'd urge you to give up on that hopeless task. There are plenty of web sites that test and rate gear; read them all and make of it what you will.