If you want to fly for an airline, your options are type rating or the CTC ACQ scheme. The instructors route is now more a way into air taxi work (allows you to build up to 700 hours for single pilot ops) this in turn could lead to work in the corporate / biz jet sector. I will definitely agree an instructors rating is the best thing to do to improve your flying standard not necessarily your job prospects for the airlines. At the balpa confernce there was an increaseing number of airlines where the recuitment criteria was either 500 hours multi crew experience or applicants from the CTC ACQ scheme, with no imbetween entry criteria for a high houred instructor. That is to get a job with Easyjet, monarch, etc, if you haven't got turbine multi crew experience then you have to apply through the CTC ACQ scheme irrespective of your hours (250 hours or 1000). Like wise I have known several instructors whom have instructed full time for a year or two and most still ended up paying for a type rating.