Interesting that Wintersong found the organic pellets useless, here they have been helpful - nothing will eradicate slugs and snails, neither do we want that to be so, too many things eat them (Uggghh). Copper tape on pots really does help, I nearly gave up my hosta collection a few years ago until discovering that, plus taking out the top inch or so of compost every Spring (that's where the eggs are if there are any). I have not found that grit, eggshells etc. helps, they just creep over it, albeit possibly more slowly.
No experience of the pellets you mention Botticelliwoman (another wonderful name), it probably works on the same principle of dryng the area out so they won't cross it - but they do, here at least.