I've done two workshops with Frans Lanting. One was a trip to the Antarctic Peninsula (co-led by his wife, Chris Eckstrom, and Justin Black). I also did an online workshop about developing a personal vision. I've got another trip with Frans scheduled for next year (to Grand Staircase Escalante, co-led by Justin Black). You can learn a lot from Frans.
In some ways, the online workshop was not what I expected. I thought it would focus on editing images, which meant to me working on images with Lightroom, Photoshop or other image editing software. But Frans comes from a publishing background -- publishing his work in National Geographic and other magazines and in his books. So I found in the workshop, that "editing" meant to Frans picking a set of photos to tell a specific story or serve some specific purpose.
I had taken 5,000+ photos of a loon family on a lake in Minnesota following the family over the summer and fall, from the adult loons incubating eggs in their nest, to loon chicks hatching, to parents feeding the loon chicks and so on. I had narrowed the set down to my favorite 500 images or so with captions and title pages. I mentioned this to Frans at the introductory session of the workshop, where we each brought 5 favorite photos to discuss with Frans and the group. Frans (reasonably) said that 500 photos was "too loony" for him and that he would look at the set when I narrowed it down to 35 photos. I learned a lot in that process (where we narrowed it down to 8-10 photos), including photos that I did not have in the set (a good establishing shot, for example, or any photos of predators). It was a valuable experience, both in one-on-one sessions with Frans and also in larger group sessions.
I've also learned from Frans's video course on bird photography. Finally, he is a Shackelton buff and that was very interesting on a trip to the Antarctic Peninsula.
I've done other trips and workshops with other professionals and have always felt I learned something to improve my own photography, although not always what I expected to learn before the trip or workshop.