They're certainly is a risk/reward balance to sub to, make sure you understand the process from start to finish. 

I hope your GC mentioned that even before you rehab the house.In Northen CA I can do much more liberal/aggressive when flip or repair the house and the reward is much more.

The decisions to whether to purchase a property subject to is a risk vs reward decision with a good dose of personal risk aversion included.  

@Serge DuLaudAllemans ....IMHO as long as your numbers make sense on a property by property analysis, based on your risk and reward criteria, its always a good time to buy.

(Due on sale clause)There are great rewards doing Subject To, when done correctly & legally.

So, when that age old cliche' of, "the greater the risk, the greater the reward", doesn't apply here...unless the REI, who is the custodian of the property, doesn't do their job. 

However, with the inherent risk (and reward of appreciation) I would say no less than 15% but I will only do 20%+ as well. 

His comment "I'll have less time on my hands" seems to indicate his lack of commitment to real estate and if you aren't committed "you.don't.make.nooooo.money, moolah, wampum, cash, "Maybe he'd be betteroff getting very good grades and trying to find an actuarial position, teaching math if that doesn't work out.Most people would not find that job particularly rewarding, trying to figure out when people will die.

But it tends to have less risk and less reward.

Key is to be specific to your situation, risk reward and scaling model.