Hi,
I was chatting with Crash last week and she brought up this thread, specifically that momentum seems to be swinging towards Xenforo and that some people have concerns about throwing away the work I've done on Discourse already. I felt the need to make a post.
From a purely personal perspective, I wish that all these reservations had been brought up earlier, but I understand that the project has been a long, slow one and that people have probably never felt an urgent need to do so until now. It's frustrating that it seems like I've wasted my time and effort, but that shouldn't make any difference to your final decision. Even in absentia, I want what's best for this community, and if you collectively decide that that's Xenforo, then you should go for it. Please don't worry about me at all.
The current Discourse test forum remains a work in progress. As I said before, I took it as far as I intended to for the time being, with further adjustments to be made after it went live. X said he would sort out the forum structure, which, as far as I can tell, he hasn't, which is a shame, because that seems to have played a big part in people's first impressions.
But I'm not a Discourse fanatic by any means. My biggest concern with Xenforo has always been that it's proprietary software, which means that TLS could find itself in exactly the same position in a few years' time, where the software is no longer supported, or is supported by means of an update that we don't want, or is vulnerable to attack. If that happens, we'll be completely stuck and will have no option but to move again. With Discourse, even if it stops getting official updates, we could switch to a fork, or fix any major vulnerabilities ourselves. The fact that Discourse is free and Xenforo is (to me) expensive is another consideration, but if you want to put the money up, then go ahead. Just be aware that it's not a one-off purchase, but $140 and then $40 for every year of upgrades/support – and the price could go up. But I can't deny that it would be a more comfortable transition from VB for the vast majority of people, which is extremely important.
TL;DR: Do what you think is best, you have my blessing either way. And good luck.