I am also facing this dilemma. MS have offered to replace my SP4 FOC. The terminology they use in describing the unit I would receive is rather circumspect. It sounds like a new unit but I believe that it is a refurbished unit.
Unless MS can categorically confirm that they have isolated the hardware problem I can only anticipate the same flickering problem some time in the future.
It is a lot of work to fully reload all my software onto another device, plus I will be without a PC for about one week. I am tempted to forget about the replacement and move asap to another brand PC tablet (at considerable extra expense) then I know that
I will only have to reload the software once and I will not lose a week without my SP.
Yes, the pain is having nothing to use/work when sending in your SP4.
Honestly, no one would know whether the screen issue will be coming back or not in future, at least for normal users like me, maybe those repair guys could tell after opened up and check the replacement unit.
My case was, totally out-of-warranty, told the support team that this is my only device for daily use, Surface Team offered me Advance Exchange Program, which they sent me a replacement unit, and I have to send back 1 unit to them within 2 weeks, if not,
I will be charged for the price of whole new unit. After I received the replacement unit, I test and stress the replacement unit non-stop for 3 days, the machine was hot during the stress. And I saw no screen flickering issue, and decided to send back to them
my problem unit after satisfied with this replacement unit in terms of cosmetic and software wise.
I would not know the Advance Exchange Program is available in your region or not as I am in Malaysia and done the swap by above program, I have no screen issue so far and touch wood with this replacement unit, I am going to install heavy software and games
maybe in near future as I said before in the thread and see how it goes.
Please mention the Advance Exchange Program with the Surface Team.