Share your experience of restoring ads or exchange server to a dissimilar hardware or what's the procedure to do it ?

There are a lot of Backup tools right now that can help you in restoring ADDS or Exchange (e.g Microsoft DPM, Symantec Backup Exec, Acronis, Veam, etc...) but the best way is to perform a P2V to your environment servers and use snapshots for your VMs. In this way, you can easily revert to a previous snapshot... We can debate for days on this topic, but in brief, I'd go for virtualization. 

Bare metal backup is the best way to restore the complete system. I've used Shadow protect and restored with dissimilar hardware.