It was probably the uber-bright primary-coloured plastic toys which initially caught my eye, but as I talked to the sales reps I learnt about their real USP: no batteries.
I have to admit, at first I couldn't see how this was particular special - surely most pre-school toys are like this. But the creative team behind WOW Toys clearly saw this design decision as a challenge rather than an obstacle, and so have put their energies into coming up with ever more ingenious ways to add play features that a purely mechanical.
Quite a few of their vehicle toys contain a 'friction motor', which uses a kind of flywheel to store energy, so that if you just push it a little way, it'll continue to travel further under its own steam in a seem lying physics-defying way. I remember having a few of these kind of toy cars as a child - they're fun and intriguing. (Even after reading a description of how these motors work on Wikipedia, I still don't fully understand it. Would love to see a diagram.)
Some of the toys also contain two moving parts which are internally geared together - so that for example if you turn one knob on the fire engine, the extended ladder rotates. The combine harvester toy has a kind of internal conveyor belt, geared with the wheels, so that if you drop a hay bale in the top, it'll pop out the back. Some of the toys also manage to make sounds (such as an engine noise) as they're played with - all still without batteries.
These 'magic features' might not sound that impressive described like this (or indeed, even with pictures on their website), but in the flesh they were pretty cool - easily the kind of thing that would surprise and delight a small child.
The themes covered by the toys are mainly fairly standard, such as emergency services, construction vehicles, farm and town, but there are a few more imaginative models, such as a campervan, an arctic snowmobile and a dragon-hauled boulder-transport cart.
The company is based in London (though the toys are manufactured in China), and they're so confident of the durability that all of the toys come with a 10 year guarantee - also unusual, as the sales rep pointed out.
One final small detail I love: all of their mini figures are doing the thumbs up.