Well, I have heard too much about ttokkyo lately, I want to wait and see if the smoke clears. The two I hear most often recommended are Fort Dodge, us made, at 50mg/ml, and ultragan at 100mg/ml.
I guess the question you might want to ask yourself is how much do I want to inject myself every week? The Fort Dodge is going to be double the ultragan in terms of volume.
Based on your access, I would go Ultra.
hth
txlonghorn