We’ve used process builder actions triggered by updates to data done in Skuid pages and have not had any problems. The data updates done in Skuid use standard Javascript Remoting methods that salesforce provices.  They should trigger process builder flows.  

Let us know what you find out. 

Rob - is there a way to launch a SKUID page or wizard from process builder? I see that Salesforce Process Builder will support APEX. Has anyone tried this yet?

We are not aware of this having been tried.  Processes are usually asynchronous, and not UI related.  What is the use case you have in mind? 

I have had nothing but issues with Process builder.

–Deployment is a hassle 
–To edit a process builder you have to clone it, lots of fragmentation
–If you use Apex Triggers, these get in the way big time
–The errors returned to the UI are not descriptive at all, they just say Flow error

My Opinion is to stay away… Stick with Apex.

I agree… they are useful for non developers but are very difficult to build and maintain for complex requirements.