The Malaysian Trumpet Snail is actually a benefit to any aquarium for several reasons. It will not eat your plants at all. This snail also will not "muscle" your shrimp off of food meant for the shrimp. The Malaysian Trumpet Snail feeds on detritus and leftover food that is underneath the substrate. It actually burrows in the substrate and moves around throughout. You will rarely see this snail during the day. Occasionally it will emerge from the substrate. A cool thing is that sometimes you will see the substrate move and you will know that there is a Malaysian Trumpet Snail underneath doing its cleaning duties.
They're like perfect clean up crew, just don't overfeed too much or the population will explode. It's great for sand substrates as the digging allows plants to gather more nutrients. However, if you plan to have a carpet then I'm not sure if they'll ruin that.