It was a team effort really, @Taloki and @Sarahsh247 really helped push this, and the amazing background image (and Super Mechs logo) were by our artist (who is absolutely amazing).
About a month or two ago I did the research and landed on Discourse after a discussion with Ilona (who liked it a lot to begin with), the project kind of got stuck until they put their weight behind it as well. So we bought it and I set it up like this.
I totally agree the old forum sucked - I've been wanting a new one since it was even made (really, can find posts from me in 2009 asking for a new forum ) and was really excited we finally got the opportunity to get it changed...
PHPBB just... Isn't all that good.