I got a job offer from a company, and looked them up online at the registrar and their status is "not in good standing." Should this be a factor in deciding whether to work for them?
This has very little legal effect. It means that someone forgot to update their annual registration and pay the fee and could be resolved in half an hour with a small late fee payment. It is a sign of slight sloppiness, but is only sometimes evidence of something more serious.
For example, if a company moves to a new location without remembering to inform the Secretary of State, it might not get the annual report notice and thus fail to file. And, a company rarely has an occasion to double check that it is in good standing.
Usually, the only legal consequence is that the company can't commence a lawsuit without bringing itself into good standing and that another company can steal its business name (if it can do so without violating a common law trademark arising from use of the name). It does not significantly change the rights of parties dealing with the company in terms of property ownership, contract rights, etc.
This said, closer scrutiny than a company without that issue might be in order and the fact that you are checking at all means that there might have been other reasons apart from this fact to be concerned.