I've found SeatGuru's window tips to be increasingly unreliable. I'm apparently like the OP in some regards--I always choose window seats when I can and pay attention to things like window placement. I can think of at least four flights in recent memory where I was surprised to find that either SeatGuru hadn't flagged a windowless row at all or had flagged the wrong row. I think part of the problem is that now US uses more configurations than SeatGuru cares to keep track of (why they deleted almost all their HP seat maps after the merger is beyond me).

One thing I always try to keep track of is which rows have two windows. Not only does this maximize your potential viewing angle, it gives a couple of extra inches of much-needed shoulder room. I find it very uncomfortable when my shoulder is wedged against the ridge between two window cutouts, and having two windows in my row pretty much eliminates this possibility. (Incidentally, at one point I submitted some comments to SeatGuru about a row which should have had two windows but instead had a blank wall immediately next to the seat, which really cut down on shoulder room. SeatGuru filed it under "mis-aligned window," which I had previously thought only encompassed weird angles.) At one point I tried to take notes on the double-window phenomenon, but I gave up on that project rather quickly. What I remember is mostly based on the 321--specifically, that row 3 has arguably the worst window setup in F and that on 321s with new interiors SeatGuru's "misaligned window" comments about rows 13-15 don't tell the whole story (I want to say there's at least one window missing in that range).