I think it depends, if you don't mind the way they look then they can offer some benefits to your tank like most snails. Its important that you like the way they look though because I took 3 adult MTS and moved them into a new tank I had just set up and now a few months later it is absolutely crawling with them. I don't mind too much or else I wouldn't have done it but if you are worried about perfect aesthetics they might not jive too well with you. As a note specifically for shrimp tanks, I've noticed that I'll set down some food in the tank and both the shrimp and MTS will swarm all over the food. I don't think it hurts the shrimp but it does sometimes make me wonder because the larger MTS can sometimes overwhelm the little dried up veggie chips I got from Jake and make it difficult for all the shrimp to get to. To be fair though this could be easily remedied by just feeding in a more spread out fashion, but just something to be aware of!