There are two schools of thought on this subject, both of which have very valid arguments. At the end of the day it would seem that it is up to the individual to decide what is right for them.

Argument No.1:

If you sign a contract and obtain a Z visa before entering the country then at the very least you are guaranteed that you will be working legally when you arrive. This is true, but the problem is that you will also be committed to work for an employer that you have never met, in a school that you possibly know very little about, and in an area that you have possibly never been to. If you are lucky enough to actually sign up at a good school then everything will be fine. But if you were unlucky and have unknowingly signed up at a school that isn't so good, then you will need to accept that you are committed for at least a year to that school. This is not to say that you need to stay if they are treating you illegally, but you will certainly find little sympathy from the authorities over matters such as low pay, high hours, poor management, crappy housing etc.

Also, it would appear that a contract signed before you come to China has little if any legal validity according to Chinese courts. Most schools who ask you to sign a contract before you arrive, will ask you to re-sign the contract in China again to ensure it's validity. This is worth bearing in mind as I assume that most people who want to arrive on a signed contract do so as they feel that it gives them more security than arriving without a contract. From a strictly legal point of view however, this is likely to be a false sense of security.

A question that I would ask would be - What kind of institution would employ a teacher that they have never met? Teachers are a very important part of any school, and the concept of employing someone for such a position without first meeting them in person astounds me, and raises questions as to the legitimacy of the school.

Argument No.2:

By arriving in China without a committment to any one employer, you are giving yourself the freedom and opportunity to check out schools before you actually make a committment. Just seeing how far the school is from downtown, the layout of the school, the behavior of students, seeing whether the place is well maintained, meeting some current foreign teachers, checking out the proposed housing etc. can all be advantageous to identifying a good school. Bear in mind that you will be signing up for at least a year in many cases so you want to do your best to make sure that you are likely to be happy there. I can't understand why anyone would want to make a committment to any employer that they have never visited! This just seems to be to be asking for trouble.

From a legal point of view there is no problem with arriving in China on a tourist visa if you are in fact a tourist. You cannot legally work on a tourist visa of course, but once you have found a school that you like, and one that is able to offer you a Z visa, they can begin the process. You may need to leave the country to actually receive the Z visa (depending upon which province you are in) but this is likely a small price to pay for job security. Most schools will cover return airfare anyway.

The biggest danger in doing things this way is that a school may promise you a Z visa even though they can't deliver on this promise. This is why you really need to speak to past and present teachers at the school as this will enable you to determine whether or not obtaining a Z visa through the school was an issue or not. If the teachers currently at the school are all still waiting for Z visas to come through then that would be a warning bell.

As I stated above, the choice will be a personal one, but from where I sit I can't see many reasons for going with argument 1, but I can see a lot of advantages of argument 2.