I don't mind escrow. I've just been scammed too many times to ever pay for anything again UPFRONT!
I'm not a developer but about the condition that you have given. You should assure that you are going to pay, if you want to pay with bitcoin, you can hire an escrow to hold the funds for you and give assurance to the dev.
After the completion of the project, the escrow shall release the funds.
It is also possible if you are going to pay upfront but for me the best choice would be hiring an escrow.
Also this thread will get much exposure on Services.
Sorry if you have been scammed too many times by paying upfront. But this is applicable for a dev that has a solid reputation in the forum, maybe the person you hired and paid upfront is just a random guy.
By using an escrow, with a small fee that you can use for the service, your money will be safe and at the same time the dev you'll hire will surely work for you because there's a guarantee that both sides are well secured through the escrow.
