Hi Kam,
In a nutshell I understand the primary difference between both the solutions is "How they are managed ?".
Cisco Meraki is 100% Cloud Managed solution. We are provided with a web portal "Dashboard" and are supposed to do most of the configuration, management and monitoring from there. [Except a very few configuration of providing cloud connectivity, Port Speed, Trunk / Access Mode etc from the Local Console Page]
Coming to integration it depends on the product you are planning to deploy.
Ex.
MR (Meraki Access Points) comes with their own "Cloud Based Controller" and Hence cannot be Managed by "On Prem WLAN Controller" or Vice Versa. Ideally it is not recommended to have both the solution on the Same Floor.
MX (Meraki Security Appliance) along with many other features brings in "AutoVPN". If you have Meraki HW both the ends setting up site to site VPN is 2 or 3 clicks. However it is very much possible construct a Site to Site Tunnel with Non Meraki Hardware too.
MS (Meraki Switches) apart from manageability portion I believe most of the features and protocols are supported and can work together with Cisco Switches.
Regards,
Ajit
AjitsNW@gmail.com
www.ajit.network