I'm not necessarily against training contracts, but I think pilots who do sign them have to get something in return aside from just that type rating.
Many companies will not have any qualms with throwing you out on the street if they decide to sell their plane even though you might have made an honorable decision and decided to honor your training contract. Some may offer you a job later on when they get another airplane, but hey... are you willing to trust them? Are they willing to trust you by not making you sign a training note?
I'm one of the guys who decided to leave the previous gig because the position wasn't quite what was advertised - I made my intentions to leave known, but I also made it perfectly clear that I will honor my training agreement. What happened? The owner quietly hired and trained my replacement behind my back and one day simply decided to let me go - no warning, last day of the month which meant no insurance for me or my family the next day, he was nice enough to give me 2 weeks pay, but that's it... Mind you, I still had around 4 to 5 months of my training obligation, and I was honoring it - no lame writeups, no sick calls, nothing like that.
Fortunately, I was on LOA from my 121 gig and they were in the hiring mode. Even though I didn't necessarily want to go back to 121, I had no choice - I couldn't leave my family without medical coverage and COBRA was extremely cost-prohibitive.
The point is that signing a training note should also obligate the company that you shall be employed for at least the duration of your training note, barring negligence and the like.