I am finally finished wrestling with Adam's shirt (Simplicity 5366, view A).
It turned out okay, but it was a real pain in the rear.
I think it was partly the fabric: very, very thick and heavy, which made turning small corners and sewing through multiple layers really difficult. I would not use a fabric this thick for a shirt like this again, that's for sure. (It is a really soft, warm, cozy fabric, though.)
But I also think it was partly the pattern. The pocket was huge and its placement was too in-the-armpit (things which I only halfway fixed...I also left the flaps off the pocket). The buttons were oddly positioned (which I did alter based on Adam's existing shirts, so I'm happy with how they turned out). I don't care for the placket style (as discussed here). I don't like how the construction of the front and cuffs leaves you with double layers of interfaced fabric (I fixed this on the cuffs by only using interfacing on half the pattern piece so that when folding only one layer of the fabric had interfacing on it...I didn't fix the front, but I will next time). That extra layering made it even harder to sew, turn out, press, and rip through the buttonholes.
If I had it all to do over again, I would try to find a different pattern. Of course, the reason I ended up with this one is that it was the lone men's button-up shirt pattern JoAnn Fabrics had to offer in the appropriate size range. As it is, I will use this one again because I am cheap and do not want it to go to waste. But I will have to alter it quite a bit.
Then there's the whole part where I cut the shirt out in the wrong size (too big) and had it half sewn before I realized it. I'm sure that contributed to some of my difficulties, too! There was a lot of seam-ripping, trimming, and restitching involved to get it to where it is, which is still pretty baggy.
There were some successes, though. I was pretty happy with my plaid-matching ability (in the places where I remembered to think about it ahead of time, which was not everywhere I should have). The buttonholes, which are always what I dread the most (I think it's because once I've cut the opening between the stitching, there is no turning back...if I ruin it at that point, it is just ruined), turned out just fine. In fact, aside from the collar issues (which are hard to photograph, but trust me, they're there) and the fact that it turned out a bit oversized, the whole thing turned out just fine.
Plus, Adam says he loves it, so that'll do!