Hi Mate,
To try and answer your question directly and keeping it very simple:
DMVPN vs SDWAN:
Have you deployed DMVPN and SDWAN solutions. DMVPN is a beautiful technology but not really friendly to deploy and maintain. I am referring to the security and routing setups. All these are taken care of 'automatically' by SDWAN. There are multitude of other benefits, but this for me is standing out.
Legacy WAN link vs. SDWAN:
Here the real benefit comes when we talking about scale. The larger the network the easier it becomes on SDWAN. Also the integrated management/visibility you get is a bonus as opposed to add and maintain an additional NMS to your traditional WAN etc.
As I said we can elaborate and I am sure people will have other and more opinions, but to me those are the ones that stand out from a practical pov. As with all cases there are benefits using either and it all depends on your requirements at the end of the day.
Hope this helps
Ciao
JC
