Gentle Shepherd is a mid-season variety in my garden this year (2016) and is performing well, but isn't very bloomy yet.
I don't think it's my whitest white this year, but it's pretty close. I think it depends a bit on the day; but part of it, too, is that it's petal substance isn't as thick as others, it is a little more delicate and crepe-y. If it were thicker, it might appear a little whiter earlier in the day (although, perhaps wouldn't bleach out as nicely later in the day?) The petals, though, are very pretty if you like flowers that look a little more delicate or ruffled. I would post a picture of it, but it's still waking up this morning and I don't have time to go digging for a previous photo of it just yet. I'll try to post a picture later. Of all of my whites blooming this morning, it is the slowest riser, barely awake and just peeking open at 7:30am.