Rhossydd,
How long is a piece of string?
Your question is very open ended, people here have tried to accommodate your original question. Perhaps if you become a little more specific and word your question differently, as in a way that include more information as to what you really want to know.
To answer the question " Should we trust figures like 107% AdobeRGB?" Do you have access to the procedure that the device was measured under, if so, and that this procedure satisfy you, then you have good reason to believe/trust that the device covers 107% AdobeRGB. Do you trust some who says their monitor covers 50% of aRGB? when you measure it crudely it does indeed cover 95% aRGB? <where crudely is with your own color device, under uncontrolled conditions>
I use a EIZO CG241W, NEC 2690 and a DELL 2407... I think the first two is rated by their respective companies to be at or around 95% or higher in terms of coverage of the aRGB color gamut. I will profile them with two trusty iOne's and the CG is just under, the NEC is over, by a degree more then the CG is under. The Dell however, is well under, but that I would also expect, as they have not made any attempt to tell me its close.
Trust.... what is your tolerance of trust? is it equal to, is it 0,00000000000000000000000000000......00000000001% or greater precision acceptable?
is 2-3% ok? is it binary, YES or NO? maybe 5-10% is acceptable?
Can you operate, at any of these tolerances when you work on any of these monitors, devices? can you tell the difference? Some can, maybe not with precision, but they can tell you that there is a difference. That difference may be to one, an advantage, a positive thing, but to another it is just not good enough.
So, in my own case, my latest monitor, an NEC 2690 has met and exceeded my expectations. I don't actually recall how big a gamut NEC claimed and I am too lazy to go looking now, but whatever the number was, it has given me enough confidence in the product to recommend it to you or anyone else who needs a nice Monitor, in its price range. Can it display 32bit color files NO. Did I expect it? NO Would i like one that could? YES! Can I afford one? NO So, the NEC fits the bill for me and I trust it to display enough or more of aRGB gamut for me to output or produce files for other people. Not that this has anything to do with NEC, but I have used it as an example here to illustrate my point.
I hope you find what you are looking for, and when you do I hope you are able to see it.
:-)
Henrik