I was looking on AMD’s website and found this: https://www.amd.com/en/products/cpu/amd-ryzen-7-pro-2700x
Is the pro version of the processor in line with Intel’s E3 processors, where they are not really I7’s, but are not full powerhouse E5’s (like in the haswell days) ?
Also has anyone heard any rumors of the new version of Ryzen to include a Ryzen 9 pro 3900X?
thanks in advance 
No. They are like the consumer counter part. Just specifically binned.
No, its not that much.
IIRC its official ECC Support (normal Ryzen also support it but its not officially mentioned I think).
There are some differences though. According to Anandtech, the Ryzen PRO support for example memory Encryption. And also some other stuff such as guaranteed availability for 24 Months.
Here an Article from Anandtech that might help you a bit:
https://www.anandtech.com/show/11591/amd-launches-ryzen-pro-cpus-enhanced-security-longer-warranty-better-quality
Ryzen PRO will be released sometime later.
Question is: Are you using it in a productive enviroment?
Is Security really important or is “Standard Level” sufficient?
As for ECC Support: works with normal Ryzen CPU though not with Ryzen APUs.
The big issue with Ryzen Pro is availability. Ryzen pro is an OEM part only. So you can’t get for a custom build directly. You have to get it off the second-tier market or get it an OEM machine and pull the CPU. Don’t expect any type of warranty if you do this. 
Same goes for the ‘E’ class Ryzen CPUs too.
I have so many uses for the Pro and the ‘E’ class Ryzen CPUs for special case usage. It is a shame we can’t get them retail.