Ideally the miners can be sent to you and I can send you payment. You can verify that the hardware is as promised, collect your fee and release payment / the merchandise.
I doubt any escrow would do that to be honest.
When I bought some miners last year I used OgNasty (
https://bitcointalk.org/index.php?action=profile;u=18321 ) to act as escrow.
I paid the purchase amount to him + his escrow fee then when I received the miners and checked they were as described and working I instructed him to release the funds to the seller - his fee.
That's normally how it works.