Neverfail feedback (I don't use, but I'm with a MS / Neverfail SI partner)
1. Monitors application environment for things that could cause down-time (disk, memory, cpu, etc) and raises alerts
2. Users typically don't have to restart their apps - depends on the app. I have 1 project involving a web-based app that requires launching new brower session. Most Windows or mobile apps do not require users to restart.
3. Failover & switchback process is faster & easier than other products
1. Won't work in a cluster environment (i.e. replicate from primary site cluster to DR site)
2. Can't be installed on a server that's a domain controller.