All the above advice is what was drummed into me during training. However since moving to London to teach all schools are so desperate for teachers and there's such a high rate of staff turnover that really it's a candidate's market! Every year we make appointments, and every year at least one candidate eventually decides to renege on their previously accepted job offer. I'm pretty sure that several go back to their current schools and use our offer as a bargaining chip to improve their salary or responsibilities.
I'm sure that when all schools were part of an LEA then yes, your name would be mud, but academies are run like businesses anyway so it's suddenly become a lot more acceptable to play the field.
If I were you I'd go to the interview for school 1 to see what it's really like and get some interview practice, if you've been in the same place for your whole career you might find it interesting to see what the interviewers focus on and their culture might really suit you even if results etc aren't as good as school 2. And then if you get a positive feeling and they offer you the job either take it or possibly ask if they'll wait. If you can get a visit/tour in at school 2 before the interview at school 1 that would be even better, as you can at least have a 'feeling' to compare it too. Most schools with vacancies are happy to show prospective applicants around and you can chat to current staff or students.
Finally each school is so different that while on paper you might prefer school 2, you might have no idea how the SLT, department structure, discipline, working culture etc will actually suit you, so if you liked school 1 enough to apply then at least try to find out how it suits you before declining an interview in the hope of getting a job at school 2! What if they didn't even call you for interview, let alone appoint you!
Hope this helps you to decide :)