I would try a couple before you buy loads, to see if they work for you. They are good in the right circumstances, but then so are some of the other approved traps which might be more versatile, and more easily adapted to other trapping situations (Fenn, BMI Magnum).
The WCS Tube Trap was sold for many years in the USA as the 'Mytling Tunnel Trap' and earned its reputation as a useful trap there, which is why it was adapted for use here in the UK.
I used one in a run between old straw bales for years and it did well in that type of site, I also lowered one in a loop of string below a br