OK, Primeval is not great - but it is well-researched: most of the monsters in the show are not known prehistoric creatures, for example, which makes sense given the long gaps in the fossil record. And the rendering is excellent - it's just that the creatures have a limited interaction with the real environment, which I guess is down to budget.
And Primeval could never approach, say, the brain-rotting stench of The Cape. SGU's poor ratings are not a badge of honour, it is a cancelled show!
As for police shows - that's pretty much a US speciality, but the really good ones are under constant threat of cancellation.
I do concede though, while I've frequently thought of British TV lately "damn, there's a lot that's good right now!", this thought has never consciously crossed my mind while watching anything Canadian. Due South, anyone?