You may have seen that answers (sometimes necessarily?) refer to commercial products. I think that such answers can be OK, however, I also find that a good answer should refer to a spectrum of products.
Think of refering to solver G*****, but also mention C**** and X****** etc. (but I actually do not refer to this particular example).
A particular product should not be a main message of an answer (which I sometimes feel it is, thus my question):
Stack Exchange as a whole discourages overt promotion; in fact, there's some text about this in the boilerplate part of every site's help pages, including ours, at /help/promotion:
How to not be a spammer
The community here tends to vote down overt self-promotion and flag it as spam. Post good, relevant answers, and if some (but not all) happen to be about your product or website, that’s okay. However, you must disclose your affiliation in your answers.
Here are some specific behaviors to avoid - even with the best of intentions, these will nearly always result in your posts being flagged as spam:
Don't talk about your product / website / book / job too much. Folks will read your answers for their ability to solve a specific problem; if you're good at doing that, then they'll find themselves more interested in who you are and what you're working on. If you respond only to questions where the answer can be something you're selling, they'll assume you're just here to sell.
Don't tell - show! The best way to avoid being seen as a snake-oil salesman is to demonstrate a solution rather than simply asserting the problem can be solved.