First of all, welcome to HN Pete -- I didn't realize you were on here.
Secondly, to answer the question, whichever appeals to me more. If it's a new programming language, or a new library, I'll generally go to the comments first and look to see the general opinion of it.
If the title is abstract, or not clear as to what it is, then I might open the article first (example from yesterday, "Do You Wanna Touch"
If the title sounds appealing, or straightforward, like today's "Here's the simple rule you need to know when using a foreign ATM", then I'll likely open the article first.
Generally, I open both in new tabs and close them as I consume them.
While I normally don't comment on the article before reading it, I sometimes comment on other comments without having read the article. If there's an article about Python, and somebody says, for example "But Python doesn't even have a print function", I can safely comment on that without having read the article.