Hello there,
Hope you are doing good on your side,
I am writing this on behalf of our company and we are expert with custom work related to different forum software. I just read your description and after analysis of your given site I came to know that one site is built on vB 3.8 and one on xenforo.
I think you should go for xenforo for this site as xenforo is highly stable and secure software. With our extensive experience we are able to provide you solution that will never let you down in front of your users.
Please let me know if you are interested so we can start productive discussion.
Thanks,
vBtise