Flyguy, I am a current Sierra student working on my Commercial Multi-Engine add on. There are others who may have more detailed insight to your question, but I'll tell you what I've come to know in regard to your question.
"Nearly 100% of Sierra grads are hired as CFI's." Sounds accurate, some pilots go elsewhere, some wash out, most have been hired as CFI's.
"Nearly 100% are hired by airlines before they even complete the program." True, up until . . . about . . . oh . . . say . . . September 11, 2001. Since then, as you probably already know, the airlines have been going through difficult times. Thousands of experienced pilots have been furloughed and are looking for work. The greatly reduced number of jobs available are being sought by a bigger pool of more experienced pilots.
Technically, the above quotes are true. However, to be completely forthright, there is more to understand. Since airline hiring has been dramatically reduced, there aren't nearly as many airline jobs for CFI's to be hired into. With few places to go, many CFI's have nowhere to go except to stay as CFI's at Sierra. With more CFI's staying at Sierra, fewer positions are available for guys like me who are just a few months away from becoming a CFI. Whether it be airline hiring or Sierra CFI hiring, the larger pool of applicants combined with fewer available jobs leads to greater competition. To get hired, you must be very good at what you do (anything from high test scores to passing check rides to quality of training and, of course if you're applying at an airline, experience).
The good news is that many airlines are steadily recooperating from 9/11. There is some hiring going on at the regionals and small charter operations. The aviation industry will rebound, it's just a matter of how soon. Also, Sierra CFI's are faring well in competing for jobs at regional airlines against more experienced pilots. Several (about 5-8) Sierra CFI's have been hired on with various operators within the past 5-6 weeks. With the hiring market being so competitive, having been trained at a school like Sierra is more of an asset than ever. Most are confident that things are steadily improving and should allow for a reasonable hiring market soon (hopefully about the time I get 1200 hours).
If you want to get the 'scoop' from other pilots around the country in regard to the hiring market, visit
http://forums.flightinfo.com/
L8R