Monoxide,
I’m a newbie in Taiwan, so think “your first few months here” when you read my post. I’ll summarize my experiences here, but if more detail will be of any help, PM me and I’ll reply.
I did quite a bit of research on the internet before coming. Did have a Taiwanese friend to ease the transition and to point out the bathrooms though. That helped. I can’t recommend Michael Turton’s website highly enough - users2.ev1.net/~turton/teach_index.html . He gives a realistic, no-holds-barred view of many aspects of life in Taiwan, with a focus on teaching English. Both positive and negative (for lack of more descriptive terms). He does focus on the stuff that tourist or recruiting websites won’t tell you.
As far as jobs go, I came without a job offer. I did that because I became convinced that the EFL landscape in Taiwan was not completely straightforward, and I would benefit from coming, learning, and then taking a job. So far, that has worked OK. Within 2 weeks of beginning my search in earnest, I am working part-time evenings. I did not use an agent. That said, I am contemplating searching for an agent now because I’m not seeing a lot of job postings for what I’m looking for which is part-time mornings, kids or kindergarten (sitting on the beach staring out to sea for the same $$ would be OK too, but haven’t seen that posted yet
).
As far as reception goes, it has been OK, but not overwhelming. Despite a master’s degree and CELTA certificate (TEFL), many places don’t seem to be biting, and it appears to be due to a relative lack of EFL teaching experience. I have been pretty straight about that in interviews and when sending out resumes, and I don’t think that’s been helpful. Some people have counseled me to make up past EFL experience, under the “everyone does it” concept, but I don’t feel comfortable with that so far. Maybe I will later. 
As far as availability goes, two things seem true. Taipei seems to be more competitive than the rest of the island, and, there are not as many job postings as I was lead to believe. The early info I got about the demand for EFL teachers in Taiwan was, “get off the plane at 9pm, be working at a buxiban the next day!” A little exaggerated, but you get the idea. I haven’t seen that to be true. Most of the schools that post jobs from outlying areas (beyond Taipei) seem to be much more in need of takers, and so, much more accomodating.
A good job site is www.tealit.com . Forumosa.com also has some, but the jobs are all different types, not teaching only, and the # of listings is far less than Tealit.com.
Good luck. Hope it helps.
Seeker4