Options On How To Purchase????

I'd like to get a better understanding on when to utilize which specific purchasing option in the preforclosure process. Would it be fair to say: -Try a short sale when you have a large second mortgage. -Try a "subject to" when you have alot of equity in the home. I really don't know, I am taking a shot at it but I would be very greatful if I could receive advise from investors regarding the way to decide which finacial / contract avenue to take given certain conditions. thank you in advance. dave barnes