I think the biggest trade-off other than a limited feature set is the fact that Edge is a paid product, whereas simulator is free to use. Edge requires a Snapvault Secondary, otherwise it shuts itself down after 72 hours, according to my SE.
Also there is no Snapmirror at this time with Edge. It's a source only product, so you could use it to replicate to a filer, but could replicate back. Ie, one-way replication.