Faced with the exact situation a few years ago, I went first with 25 then up to 28, where I'll probably stay. I'm not commuting anymore, but cycle up to 200 miles/week in retirement. My main consideration in not going larger is tire mass. I do a lot of climbing.
I saw somewhere that with that rim width, the wheel is very slightly more aerodynamic with 28 than with 25.
One extra reason for not going larger is that I share spare tires and tubes with my wife. Been doing that for forty years and it's a hard habit to break.