While the first cost to get in mobiles may be lower, the longer term numbers may not be as impressive factoring in appreciation.

If you factor in closing costs it might be 3 years to start showing your benefits of a refi

Not to diminish their importance but aside from the legalities, ethics and complexities involved, if you have actually done subject to's, what are the overwhelming determining factors that would make a property a candidate for a subject to?  

Could be a motivating factor.

You may end-up being a 2nd for ever.

I said, "God, if you'll let me breathe like a fish just this one time, I'll serve you forever".

Apparently, they can't stop you unless they've stayed in that day and bolted the door in which case you won't have access.But they can't do that forever so try every day after if that happens.  

They tend to hold property for a long time, usually forever.

They talked forever.

Regardless you have money or not, I think one of the most important factor to be a successful RE investor (or having your own business) is networking.