I have setup a site on mage 2.1.2 and have Paypal Payments Pro up and running.
Payments do process fine, but the transaction takes a long time... up to 10 seconds.
My site is in production mode, is reasonably performant for the product pages and has plenty of resources available.
The issue is an extremely slow card processing with Paypal Pro.
Part of the issue is that it does a two stage process... so, the first stage takes a couple of seconds... with the nice processing indicator spinner on the page, but the second stage takes another 5 seconds or more, with nothing to indicate to the user that the page is still processing, then finally the order will go through.
Issue is that I'm sure users are going to be impatient and assume that the page is no longer processing and they will refresh or nav away.
I'm having the same problem with very slow processing.
The checkout will also hang/stall occasionally and the transaction will not complete.
ElliotGage, did you find a solution?