Comparing schools

Martial arts schools may appear to be offering the same arts as one another: tai chi chuan, kung fu, self defence, baguazhang, shuai jiao, chin na, qigong...
But are they offering exactly the same arts? Are they teaching the same skills? The same syllabus?
No.
Every teacher is different. Every school is different. The chances are that you are not comparing like with like.
Consider:

What is the school's speciality?
Do they have a detailed syllabus in place?
Is the art authentic?
Can you read reviews/feedback?
Are they interested in the philosophical side of the art?
What is the age group in the class?
Does the school seem to be welcoming and friendly?
Is the school macho?
What is the emphasis: sport/competition/MMA/self defence/traditional teaching?

Take into account what you are looking for from a school.