Well, we were in the same boat: about 100 users with persistent disks in (dedicated) Linked Clone VMs. We have been using Roaming Profiles though for years and they are just fine. Sure, users with huge profiles (mostly caused by huge .pst files) are gonna see some additional seconds but they should be punished for using it wrong anyways. 
Anyway, we made the switch to (dedicated) Instant Clones and it behaves just like we're used to with Linked Clones.