I have Lucky's Tale, Adventure Time (it was 5$, but it wasn't really worth it), should be getting Eve: Valkyrie, whenever the code gets sent.  

Only bought the one game, been trying to try out as much of the free stuff as I can.  There's also like 2 free games, Farlands and InCell that I found.  Neither are very gamey though.

There's some VR "experiences" that are available that are very cool; that should be made into games honestly.  The Oculus Dream Deck has some short but amazing experiences.  

No way to calibrate the lenses individually as far as I can tell.  I think all of the lense adjustment is done by either adjusting the headset vertically or the slider that separates the lenses horizontally.  The slider doesn't seem to make any real difference if you're wearing glasses, at least it hasn't for me.  But if you have the headset set up where it looks perfect, and then it starts to droop on your face, then things start to get blurry.  There is a strap on the left and the right side, as well as one on the top of the headset to adjust fitting and placement. 

I have tried the GearVR a couple of times, but only for a few minutes.  Screen door effect is much smaller than the GearVR, and it's not even noticeable in some applications.  In Lucky's Tale it's not noticeable, but in the Oculus Home it can be fairly present and noticeable. 

The lenses are easy to clean.  They recommend just using a dry optical lens micro-fiber cloth.  They haven't accumulated very much dust, maybe a little.