PayPal payments can be easily reversed. Unless an irreversible system like Liberty Reserve is used, it would be better for you to handle the payments.
Does BitCoin Market fill orders partially if the entire amount is not available?
Yes, partial orders are filled, if the whole amount is not available.
Charge-backs are a weakness of this system. I’ve thought about ways to help rectify this weakness. I’ve come up with two so far…
- A user rating system, based on past trades and/or time.
- Forcing the buyer to keep Bitcoins in his/her account for a period of time as collateral.
I haven’t seen a fool-proof exchange method yet. Some would argue that LR can’t be trusted or a centralized account is begging to be confiscated. Who knows… But I do know designing something that fits the needs of a large audience is hard work, especially when our community is still so small. PayPal is fairly common to all.