I have earned my living as a Motorcycle Mechanic since 2001. I did not attend any technical training school what so ever. Not even in high school ! I was hired by a dealer as a clean slate, PDI technician for $7 an hour. After five years at the dealer I was making $12 an hour (I live in western NY). By that time I had the skill set to do any engine overhaul, tranny rebuild, crash repair and diagnose any electrical issue with ease. So dont plan on getting rich unless you work for yourself, stay in a warm climate with year round riding season, or do a ton of side jobs.
I did attend three H-D training courses at MMI Orlando and was impressed by the facility and the H-D instructors. I have also been to WyoTech in Fremont, CA for two Ducati training classes. I was not impressed by the school, especially the shop bikes were piss poor.
There were a few young MMI grads that came to work at the dealership I was at. They were very green, had little troubleshooting skills and HUGE debt (from MMI tuition and tool purchases).
Take the risk and go for your dreams!
READ every book, service manual, and technical bulletin you can. MASTER the fundamentals of electrical diagnostics. You cold build a reputation/career on fixing botched electrical repairs.
Live it, eat it and breathe it 24/7 and you might make it as a motorcycle technician.