I'll take them both.
John, you're a mod here, and acting as escrow, so you'll be the one holding my money and receiving his machine? That's a lot of value in your hands, and while the only reason I feel comfortable even talking about this transaction is because you are involved I would need some personal details to know who I am actually dealing with here.
If that's not out of line, and the seller agrees we can move forward.
300 BTC is a fair price for 2 pre-orders for B2.
Since the Avalon owner is also a member of this forum I'd politely hope he would verify the orders and such.
I'm only holding the deposit at the moment for his transaction, as stated above.
As per my rep here, I've been doing escrow for some time already. I'm currently holding over 2k BTC of others funds, the greatest being 1k BTC of the forum for an indefinite period of time, and others from various members here. I've lost count of how much funds that have passed through my hands so far, but a few large-sized transaction that I can make public here is a 2200 BTC TX some weeks ago (
https://bitcointalksearch.org/topic/m.1568855) , and multiple large-sized AM share auctions like this:
https://bitcointalksearch.org/topic/asicminer-auction-2000-sahres-144574 . I have a thread here too:
https://bitcointalksearch.org/topic/john-john-ks-escrow-service-previously-known-as-johnthedong-141672I don't really keep a ledger of my escrows as it would eat up too much time to do so, but I generally escrow 2-3 transactions daily.
As for security:
So everyone's asking me how I store escrow funds - I store them in Offline Armory with the seed backed up in encrypted paper wallets in multiple places including but not limited to a bank vault and lawyer's safe.
As always, please do your homework before choosing an escrow (or even sending coins in general!), so feel free to do your own research and stuff before choosing to trust me or not.