So after reading several pages in this thread, I'm still uncertain whether BTC-Arbs is a legitimate business, or is a ponzi scheme which will rob me of my coins within a few months.

Is there any conclusive proof that there is some shady work happening behind all this? It appears everyone is able to generate interest and withdraw funds with no issues, and if they are making a cut out of all this, it's in their best interest to make their business model work.