In the book "Adrift" by Steven Callahan the author's solar stills got him through times of otherwise no water. He was in perfect conditions, though: very moist source (seawater) in very hot & sunny weather. IIRC he netted about 2 pints/day from each still. His stills were small and purpose-made for use at sea although they fell apart after a while.

When I read the book, I remembered all the nay-saying about solar stills & the sweat equity they demand. While they certainly won't produce bountiful springs of water, I think they should be among your options IF:

1 - you do the work to set them up at night, not out in the broiling sun

2 - you utilize a moisture source other than the ground itself: cut up vegetation, seawater, etc.

3 - take advantage of natural depressions (or available containers) rather than digging big holes from scratch

I think solar stills are best considered adjunct water sources that are nice if they work out, but are not to be depended upon as a primary source. I wouldn't throw out the entire concept, though, as seems to be common. I think Callahan's real-world experience with the stills is not to be dismissed lightly.