I have found the soil and animal safe ones just as effective as the others, tho' like them, you need use only a few and as rarely as possible. I have been given a pack of some material that swells and deters them according to the pack - I shall try that - with some doubtfulness - when the time comes. After this warm winter, we will surely be overwhelmed without due care and attention - or with it in fact.
One of the things I like best about the wildlife friendly ones sold here is, apart from their effectiveness, their name - Escar-Go!
Very much agree Verdun, they climb the brick walls, happily go over the sand heaps. nothing physical of that nature has ever worked here. Only nematodes, and that was just so much work for a short term of protection, and the copper as long as they don't climb the walls and drop into the pots, baskets etc., which of course they do. Lots of birds and frogs here, but also LOTS of slugs and snails too.
I find it easier to grow things they don't like, they don't like my ferns, aquilegia, dianthus, scaboius, roses, camellias etc, none of those are touched. Occasionally I make a mistake with plants, I pit some lovely orange asters in one year and the very next morning they were stalks
I have pretty much worked it out now, they like the odd cronch on the japanese anenome but I think it's desperation They hate annual geraniums too and evergreens.