I’m a friend of solving immediate issues, they give you some experience with debugging things, and also the obligatory “yes, I solved it” feeling.
I see that in the monitoring community a lot. Problem X is there, doesn’t work. Another user jumps in and suggests to replace it with project Y. Keeping a question with a discussion and a possible solution helps many others who find the topic years after with Google. I do see my knowledge input as investment into the future, not to answer that again and again.
Still, if many community members choose Ubuntu LTS, go for it. You are now in the first steps where such a decision can be made easily. At NETWAYS, we’re also going the Ubuntu route these days, and my Discourse instance runs on 14.04 at the moment. dist-upgrade to 16.04 is planned, 18.04 will be out this year too.
The good thing about the container image is that you don’t have to care about Ruby, gem, etc. version dependencies. In terms of security aspects in such an AIO package, I do have the feeling that the Discourse team acts responsible with announcing and forcing users to upgrade on possible CVEs and security bugs.
Cheers,
Michael