Im waiting since June for the windshield for 2017 subaru forester with eyesigh , they said its on back order. Do the aftermarket windshield work well ?

I believe if you install an aftermarket windshield, it will need to be calibrated per manual. But try to source an OEM Subaru from elsewhere.

I just had the windshield of my 2017 outback replaced in under a week by safelite and have no problems. I had to go to their shop for installation.

Not with vehicles equipped with eye sight. With the eye sight system a factory windshield must be installed.