The number of replies stands for the just that, the total number of replies (not who has posted)... I was referring to a count of how many users had posted...
It is working fine for me - I have 25 add ons (dont know if that is a lot). I use the standard xenforo style with a few customisations (nothing major).
Zero issues to date - if anything it is more stable that 1.3.1 which I was running before.
Looks perfect - have been looking to replace xen media pro due to its lack of support and some basic styling issues.... this looks like it fits the bill....