Unfortunately I've not tried the sneeker myself, though have heard good things about them so would also be tempted. Just happens that the defender seems more available, I think it is more commonly issued, and (once worn in, which does take a while) I've found it light and comfy enough for me and tends to suit the mix of dryness and bogs I tend to encounter very well indeed.
That said, I've just bought a pair of meindel desert boots, which I think are also MOD issue though not as common on ebay, just to see how they work - Suede and fabric jobs, not waterproof. It is too early to call yet, but first impressions are that they are a much more sculpted fit to the heel, and very decently built, but seem to generate more sore spots in various places. They almost certainly won't last as long and (IIRC can't be resoled anyway) but of course are for quite a different application.
I should mention that there is a lot of rubbish on ebay too, quite worn ones still going for a fair rate (presumably for other uses than walking) so one needs to be careful. Standards seem to be sinking unfortunately, so where once I'd buy super-grade with a fair degree of confidence, these days I tend to go only for those where there are clear pictures of the actual boots. Especially their soles, since a re-sole now costs around £80 which is no less and sometimes more than a nearly new defender.
Cheers,
Kev