There's plenty of good advice in this thread, but ultimately you won't know until you work there. After 20 years in the business, what I've done and would advise people to do, is to negotiate a 6 month contract-to-hire arrangement. This way it's all out in the open that you'll be evaluating each other and there's less hard feelings if you walk at the end of the contract.
That's an interesting angle. I've always assumed that the C-to-H arrangements were for the benefit of the employer, not necessarily the employee.
It can be to the benefit of both. The employer doesn't have to do all the onboarding until they figure out whether it's going to work. If they employee doesn't like it they have an easy out at 6 months that doesn't harm your reputation as much as bailing out shortly after taking the job. That easy out also prevents you from staying longer for fear of establishing a job-hopper reputation. At your next interview when asked why you left -'It was a 6 month contract at the end of which they offered me a full-time position but I didn't feel it was a good fit'. That's a much better story.