My Brunnera 'Hadspen Cream' tend to green up in the summer.

I had crispy browned leaves on the variegated (cream and green but forget name of cultivar) ones I had, they just would not tolerate any dryness or too much sun. I finally tossed them, they looked great when they emerged fresh each spring but went downhill into a crispy mess as the season progressed.

I don't have that problem with the plain 'ol green brunnera. They wilt terribly if the soil is dry, but the leaves don't burn, and after a good soaking they perk right back up no worse for the wear (the more consistently moist the soil, though, the larger the leaves, they really are moisture lovers), and they tolerate more sun than the variegated variety in my experience.

Also, the plain 'ol green standbys are much more vigorous than the variegated ones, too (again, in my experience).

FWIW - I don't care for Jack Frost either, but hey that's just a personal taste issue.

I like Looking Glass better than Jack Frost - looks great with white astilbes. But it definitely has to be kept moist or will succumb to hot or dry weather. It might be a little too temperamental for me - its in its 2nd year and doing fine but I toss some water on it almost every day.
I think Hadspen Cream is a beautiful foliage.

My favorite is 'Langtrees'.

The species is a beautiful plant. It reseeds a fair bit, which I like.

Nothing like it for blue flowers in spring (less of a show this year due to the major cold snap in early April, but the plants came through fine).

Eric - definitely agree. What a stunning color blue in the spring garden!

I think the foliage of the variegated cultivars is beautiful but don't get the same flower effect as the regular green brunnera - the tiny blue flowers get lost against the variegation. On the all-green brunnera, though, those thousands of tiny B-L-U-E flowers are just beautiful against the deep green foliage, they really stand out.