I've been trying burst training since the start of this thread. I initially started doing the 30-45 sec. sprints, completely stopping for approx. 2 mins to recover, then sprinting again. After 2 strained/pulled hammys, I went back to walking at a slow speed for recovery and all has been good since then. I've definitely noticed some good results. I'm getting leaner while my legs/hips have been getting stronger, and my energy level seems higher. I'd definitely advise anyone who is starting this to take it slowly and to keep loose during the recovery 2 mins, rather than coming to a complete standstill, as some videos suggest. I get bored with the usual longer cardio routines, whereas I find the 20min burst session very enjoyable. Also, I've yet to suffer from a cardiac arrest as Killthesunshine warns, but since I work out at a major hospital gym, I'll take my chances.
