Should the solution be the first instance of the correct answer or the most recent? Scheduling an Apex Job through the ui
Also, should an early comment influence the selection of the answer which is marked as the solution?
There is no correct answer for this, it's simply up to the user who asked the question to accept whichever answer provided them with the most useful and helpful information.
Answering first will often improve your chances if your answer is helpful and informative, but if the person who posed the question doesn't visit for a period of time (before accepting anything) and then sees a list of answers it's up to them to choose which answer best suited their needs—they have no obligation to consider which answer came first.
As the asker, I will give you my rationale. I chose Derek's answer because he took the time to provide a screenshot, something that could conceivably help future readers of the question.
As for first or most recent, you were 1 minute apart, when both answers are posted at the exact same time I'd say you win some you lose some. I upvoted both because they came in at the same time.
If the difference is more than a few minutes, I would always choose the first answer, unless a subsequent answer is that much better. But still vote for both, hint to all reading this, vote often!
Your earlier comment is what makes this murky. I will be honest I overlooked it. I think this will always be the askers choice, and it will be a question by question decision.