We integrate SD-WAN capabilities with Fortinet FortiGate frequently. Integrating SD-WAN is very easy and almost plug and play. In many cases, it's accomplished by using the built-in features. For more advanced SD-WAN configuration, it's very well documented and described in the Fortinet documents, which helps significantly. It works flawlessly most of the time and is very easy to administer.
I haven't worked extensively with Fortinet Unified SASE yet. We will probably work more with it, but since Norway is quite a small country, we don't have the same use cases as America has, which has many branches of their customers. Our big clients are usually what the US refers to as a small business. We have many smaller locations, which have fewer security needs in a SASE way, as of yet. We are starting to see that the thinking about SASE is changing and more companies are actually starting to open up for the idea of having SASE. I still haven't actually implemented it. I've done several labs with Fortinet and workshops with them. I don't have the experience to actually say how it works because I haven't implemented it with a working customer yet.