We have used SM, Airwatch. MobileIron, Xen_Mobile, MAS360 ; Meraki is a good MDM product and the advantages are cost, single pane of glass and ease of use. Where the more feature rich EMM's come in is integration, features and functionality for large enterprises. This also differs if you are looking at cloud versus on-prem.
We are a MobileIron vendor/integrator but it depends on client requirements, for small clients, or ones with leaner IT SM is a great choice. If rich features, integrations and application tunneling capabilities we recommend MobileIron.
It really comes down to do you just need an MDM product or do you need an EMM product?