I'm not able to get screenshots, but the Blu-rays are the best I've ever seen the show. They're much better than the files I downloaded from Apple TV, and are light years ahead of the DVDs. Shots are crisp, colours stand out, lighting is just right, the effects look great, and to be honest it looks like it was made yesterday not 30 years ago.
The downside is the packaging isn't the best, and getting some discs out can be tricky. There's no extras aside from a very low quality version of The Gathering, and the other TV movies are not included either (we think possibly because of rights issues with TNT). We also lose the widescreen live action shots, but to be honest they added little, and we gain much more by now having uncropped effects shots in 4:3.
The Blu-ray boxset is 100% worth getting, especially if you can find it in a sale.