Mine arrived today and I'm afraid to say they are pretty awful, as a number of others have stated...
I've taken part in group-buys before; but not for keycap sets (a relatively new interest), so I didn't really know what to expect in terms of quality; but for 65GBP this is disappointing.
I think the photo illustrates most of the issues; mismatching colours, brown-on-brown instead of orange-on-black, no obvious attempt at deflashing on many of the caps, non-centred blurry/wonky/inconsistent legends, bad kerning, other marks, etc.
Interestingly the 'Hold' and '\|' keys are much better than the rest (in colour, finish and legend clarity), but seem to have been made/labelled with a different process (not sure which). The 'big-ass' enter cap is completely different to the rest in every conceivable way.
The first few caps I've mounted (using a DREVO Calibur 71 for now) are sticking when pressed. I'm not sure if that's due to the thicker caps hitting the back-lit switches, or the stem diameter being too large. I'll try them on a different board with Cherry blacks later.
The Skidata set actually makes the standard Drevo keycaps (which I purchased these to replace) look rather good quality by comparison.
I have sympathy for UKKeycaps/MechSupply (Joe?), as this appears to be entirely down to Devlin having abysmal quality control, and leaving him to deal with the consequences.
I'd not hesitate to take part in a future MechSupply/UKKeyCaps group buy in the future; but I'm not going to consider anything from Devlin again.