For example, I'm looking into buying a band saw. I've never used one before so I don't know which features are important in a band saw. To make the best out of my money, I would like to know which features are important when comparing band saws. Are those type of questions acceptable or are they too opinionated?
Questions on tool features and their functionality would be on topic, in my opinion. These can be objectively answered, since tool features were (hopefully) designed for accomplishing a specific task or making certain use cases easier.
However, questions on tool brand X vs brand Y would land on the side of shopping advice, and be off topic.
Yes. "Gear talk" and trouble-shooting equipment is often a big part of just about any half-way decent site on these subjects. Let's not lose sight of that. Sometimes we have a tendency to wallow in these generic "Wikipedia-answerable" questions, and fail to remember sites like this when we have our own, personal varieties of real-world problems that need solving. Selecting, setting up, using and maintaining the tools of your craft really should be a big part of this site.
An example of a good question is something like this:
I'm looking to buy a band saw, and want to know what features are important. I'm going to be using it to build a table and chair set for my dining room, using maple and oak.
Specifically, what does a higher power rating on the motor do for me with these woods? What size is appropriate for this kind of use?
An example of a bad question is more like this:
I'm looking to buy a band saw. What should I look for?"
The former question gives enough detail that it's possible to describe the different features. The latter is entirely open ended, and doesn't give any way to give good advice: a good answer would be closer to a blog post, and the asker clearly didn't do any research of his/her own before asking.
From my experience with other sites, particularly Parenting, where this isn't uncommon, it's important to either have some use-case specifics or to have a somewhat limited question [asking about a couple of specific features, for example] to get a useful answer that's not a blog post or an advertisement.
Standard reminder ... and yes, I know pointers are frowned upon here but it really is worth reading the original essay ... to the "how to ask questions the smart way" piece at http://www.catb.org/esr/faqs/smart-questions.html
All our questions should meet those guidelines for "helping us help you."
All our _answers _ should try to be more patient, though!
(Thanks for pointing out that i'd miscopied the uri.)