Sorry not sure what topic this belongs under. but…
Have you considered a free hosted option? I know they are not quite the same thing but I’ve been using disqus.com for comments on my blog. It’s awesome, they host it. That means they deal with spam issues, they deal with upgrades to the system. Of course there are tradeoffs
They have 1 login for all sites: Good: less hassle to use, track all threads from one place, reputation carries (not a spammer on one site assumes not a spammer on others) Bad: less granularity
They probably plan to mine for data: Good: can tell trends, etc. Bad: privacy
Sure I could host my own discourse installation but what I’ve found running a blog for 12 years now is it’s no fun to do it myself. Sooner or later the spammers find a way in and I have hours of cleanup to do. Even if they never find a way in I have hours of maintenance. Disqus is mostly install and forget. Even cooler for wordpress it’s pretty much risk free because it manages to insert the comments back into the wordpress database so if I ever quit disqus I don’t lose my comments.
$49 a month is way too much for discourse for a personal blog that might only see 25-250 forum messages a year. Seeing as how facebook comments are free and disqus comments are free it seems like you might want to consider this as an option. Maybe the free option you reserve the right to insert some ads or something.