I have most of these dvd tutorials so will offer my input:
The JBT has some nice topics/techniques covered, however the production value is very buggy. If you are french speaking, you will probably have no problems, however for other languages (english in my case), there are subtitles that stop displaying halfway through on some videos, making that particular video useless. Sometimes a different language (spanish) subtitle will display instead of the english. Also they sent out PAL format DVDs to the US which uses NTSC format, which means you will only be able to view the dvds from your computer. They also mislabeled the dvds 1 and 2. Personally, I feel like I paid to test out the dvd since these are bugs that should have been caught very early on and fixed. I also think that they should offer to replace the discs when these bugs are fixed.
Miniature Mentor has seem decent tutorials, however most are specific artist\'s techniques. So if you paint a certain way like using thin layers to build up transitions, then some of the other tutorials will be useless for you. I found the Alan C video to be different from my own, so I\'m sure it works for some people, but I found no value in it. It\'s nice to see how other artists paint, but once you find a style that works for you, the other vids are not going to be that valuable. I like the Jen Haley video though, they get into more detail with the thought process instead of the other videos which show a lot of the same painting over and over again.
Also they seem to be listening to what customers are saying and implementing those suggestions into the newer videos, so they are improving and they should have some nicer tutorials coming out.
The Kaple.dk video is really only 20 minutes of video. The rest of the \"dvd\" is actually just text and picture tutorials just like on cmon. I found it aimed mostly for the beginner.