I'm running the new driver for 2 days now and it has been night and day. So I assume your problems will be solved also.
The only things we need to wait for know are the sleep fix/update from microsoft (comming somewhere in the beginning of 2016 they said) and the microsoft version of the display driver you just installed. This will not really change anything I think but then
you'll be running a microsoft tested drivers instead of just the Intel generic driver for your chipset (which is fine...)
Your unit is not faulty, let me stress that, the problems you've been having before is just because the last display driver update microsoft released contained a beta driver (you can see here: https://downloadcenter.intel.com/product/88358/Intel-Iris-Graphics-540-for-6th-Generation-Intel-Core-Processor
) and had a lot of known issues that where rather bad...
It solved some previous issues users had but not all of them, Intel then released a bit more mature version of that driver which you just installed.
I think it's much better and actually makes my Surface reliable (always wakes from sleep and no freezes/lockups anymore), Miracast actually works know and so on... There are still some known issues (mostly incompatible with some games) with it but I suspect
Intel will release more driver updates in the coming weeks.
But we always have to wait before microsoft releases those updates in one of their sanctioned updates via the windows update platform and there is always a bit of time in between, one or 2 weeks probably...
If my system is reliable I do not mind waiting but the beta driver was so bad I went ahead and installed the generic driver. I'm glad I did.
So in conclusion, it's mostly Intell's fault of not supporting their new silicon with proper drivers from the get go. Maybe also a bit of Microsoft's fault for not applying enough pressure on Intel to come up with solid drivers? They had to use these chips
as the market "needed/suspected" them... It's just really sad that so many people have problems and bad experiences with expensive devices just because drivers are not ready.