Snails As Part Of A Tank Clean-up Crew?

Just wondering what peoples opinions/experiences are using snails as part of your tank's clean-up crew? I'm referring to purpose bought snails (not ones brought in on plants etc and which become a pest).

I picked up a couple of 'long nose' snails at the weekend (I found some old forum posts on here in which people seemed to be saying that they're 'Rabbit' snails?) just to add a bit more variety to my community tank and didn't expect them to do much in the way of clean up. However, I've been pleasantly surprised at how much they get about the tank and how well they appear to be clearing algae.

I've got some rocks which are ready for an algae scrape off, but as you can see in the pic, one of the snails has cleared a nice swathe of the algae off the rock just this morning.

I did introduce some Cherry Shrimp a little while back for that very reason but I think they were too young/small and either ended up becoming an expensive snack for some of my fish or were too afraid to come out and died off. I know shrimp are good at hiding but I haven't had a sighting for ages now.

As such I have introduced 2 Amano Shrimp recently, both of which were larger than the Cherries and the largest of the 2 looks almost fully grown. Since introduction the larger one seems to be fine, doesn't appear to be being bothered by any of the fish and I've seen it every day, but no sign of the smaller one!

The lfs I went to over the weekend did have some fully grown Amano Shrimp but after already having made a few purchases over the weekend buying anything else would have got me in bother with the OH! I may go back and pick some up at a later date