Ah. Unjung beat me to pics of a button down, but here are some additional for reference.
Here is the Modern shirt, and for comparison an OTR BB shirt that's been washed about a billion times. Intent of this is to show how the collar points rest in relation to the associated buttons. The BB shirt is where I think they should be, the modern shirt looks off.


This image shows where I believe the points should rest, more or less, when worn. The buttons just seem too far out to the sides to me. Collar is a little wider than spec'd, but may shrink (hopefully).

The result is, when worn, the collar seems a bit wide, and given the height of the collar itself (next pic), it tends to rest too far into the shoulders on the side of my neck.

This is the height of the collar. It seems the collar itself is about 1/4" too tall based on where it folds.

So... would I buy from them again? I like the fabric. Every other measurement is pretty close relative to the shirt I used as a reference, factoring in a shrinkage allowance. shoulders are a bit wide. The fit should be ok when it shrinks up. I apparently made a mistake and selected darts on the back instead of no pleats. I don't like darts, so here comes the seam ripper (carefully one at a time). I do not like the collar at all. If it doesn't shrink, and relocating the buttons doesn't take care of the spacing, I will not repeat this at the price.
Here is the reference shirt back to back, so you can see how much smaller the collar is. Granted, it's not a button down, but a similar effect is there with the BB shirt. this one was made for me while I was living in Singapore.... oh, if I had only known how sweet that was at the time...

probably more than you ever wanted to know about a modern tailor button down.
The other two I'm testing are Mytailor, and monikerwear.