DS is right as usual...don't discount the experience you have!
I would recommend Chiang Mai over Boland, for sure, for all those who want to pursue a TEFL cert in Suzhou. I don't know enough about the others to rate one over the other.
However, at least the Chiang Mai one has some affiliation, albeit probably tenuous, with an actual institution of higher learning. As far as I know the others are probably just some guy with a domain name, a marketing budget, and a big roll of certificate forms.
Personally, I wouldn't waste my money and time on an online TEFL cert. I'm not too sure even the real-time ones are worth it, much less the online ones.
In general, as far as getting a job goes, a cert MIGHT be worth it if you don't have a college degree and need a pretty paper to wave before the eyes of the school managers. Here it doesn't matter much which cert you have or where it comes from...just shop price. Otherwise, the effect of a cert on your China job hunt is generally VASTLY over-rated...especially by the companies who provide certs in the first place.
Again, the most valid reason to get a cert is to improve your own confidence, learn some techniques and methodologies...generally make yourself a better teacher. An online cert can't do this very effectively; you're talking a real-time program or nothing.
I've never been disqualified from a job because I don't have a certificate. I do have multiple degrees and lots of experience, but even the jobs that specify degree, experience, AND certification have all given me an audience. When I volunteer that I don't have a cert, the managers invariably chuckle and say, "Don't worry about it."
Be sure and not confuse a "TEFL certificate" with a "teaching certificate". The former are often issued by places like "Jim Bob's Bait Shop and TEFL Certificate Emporium" and don't really count for all that much. The latter are issued by a state or provincial government body and can get you a real job as a real teacher...once you've completed the required college hours and more.
The REALLY top jobs will impatiently wave away the former and insist on the latter.