I've had a chance to compare the Oxford and the Opticron. The Oxford is 10x 30mm and the Opticron is 10x 26mm which makes the Oxford just that bit larger and allows more light through as a result. The led illumination is the same and is really bright on both and they both handle the same being of very similar construction and size. In good light though there is no need to use the led. Its when viewing with the loupe at at varying distances (1-3 inches) away from the eye the difference really can be seen. The Opticron falls off at the side the further away it is moved from the eye especially at 3in from the eye when the undistorted viewing area reduces to approx 18mm. The Oxford performs much better and remained practically undistorted across the the lens. With either loupe close to the eye the performance is similar but 4mm makes a difference and I preferred the overall performance of the Oxford.
I have to say that the plastic cases provided leave a lot to be desired and I do not think they will last long.
Santa will be bringing me the Oxford - you get what you pay for - but I think that there is a place for the Opticron. At £15 the Opticron appears good value and I would think it would suit most occasions especially if there is a limited budget.
Neil - looking in the battery compartment there is a bit of space which would allow some careful drilling to provide a couple of holes to attach a cord to it in a similar way to the picture below where I "modified" my IR remote control. "Guarantee may be affected"
I also think that the lenses are recessed sufficiently to protect from scratching.
All this is subjective of course.
JohnB