If you are hoping to get a job in the more prestigious language schools and universities, then where you do your certificate may make a difference. No matter whether they are good or bad, different programs have different reputation. Potential employers may be aware of these reputations.
That said, potential employers are also aware that many more TEFL certificate programs are popping up everyday. It is difficult to be aware of all of them. Just because a program is new doesn’t mean it’s a fly-by-night, easy-money-making scheme. But of course there are a lot of unreliable or temporary and not very good organizations that provide much cheaper course and certificates.
As in other kinds of business you will not be able to corner the market and stay the leader for a long time if you don’t offer something really valuable or any demanded service. You may be able to get a sense of how serious a program is by talking to them and doing a little bit of research. Look through their web sites and mail them straight forward. Of course talking to past attendees is a good idea too. But you should not forget to discuss everything with many of past attendees to be aware of the course objectives. Especially out on the internet, where anonymity breeds bravado, many people are grinding axes for reasons that have little or nothing to do with what they say they’re grinding their axes about.
There are many quality certificate programs out there, some with very good reputations. Any potential employer would be impressed by such a certificate. But if variables such as convenience, cost, and length of the program come into play and you simply can't make it to one of these well-known programs, that's no reason to give up the idea of taking a course. One is likely to be nearby, and there are some online programs.
As with all educational institutions, much depends on the teacher(s). Some programs with good reputation unfortunately may have bad teachers from time to time, and programs which are on the first site not very steady and reliable, more often have quite good and skillful teachers. Your fellow course students will also play into making the program a successful one or not. The course is worth attending just to come, meet interesting people, discuss various problematic questions and solve them.
When taking a course in a non-English speaking country, you may also find local teachers as your classmates. Local language learners can benefit from the communication with these teachers. These types of insights are more apt to come out in a TEFL course than they would in more casual, everyday interaction you might already experience with local teachers.