Terremoto,
Here is my take on the videos.
Structure
All his DVDs follow this structure
1. A short introduction and thank you from Mario. DVD Volume 1 has an additional section on "technicalities", in which Mario revises the basics like CBL, CBLT, copa and drop hand catch, which from the fundamentals upon which advanced moves are layered. I bought Volume 1 simply for this: it's important to constantly revise your fundamentals and execute them clean. For this I always look at this section from Volume 1.
2. Each individual turn pattern
i) A demonstration to verbal count
ii) Actual breakdown of the combination
iii) A demonstration to slow music
3. Except Volume 1, Volumes 2 to 5 have demo clips of his social dancing. I find these segments to be truly inspirational, because they demonstrate what can be done socially with a lady who doesn't know what you're gonna do. Unrehearsed with nothing but solid connection and tension, I always get more inspiration from watching clips of social dancing than choreographed performances.
One small downside: if you like the music that is overlaid on the dancing, you're out of luck. The salsa group that did the music for these, Chocolate on Ice Cream, are gone and I can't get their CD anywhere.
Turn Pattern Structure
There are 9 to 11 turn patterns in each video. Each turn pattern is pretty long, and usually consists of about 4 to 5 moves. I like Mario's patterns because they are based on solid fundamentals: nothing too funky or ridiculous or contortionist. Some of these moves you will find are 'easy' moves done in new ways: variations of copas, CBLTs, and so on. Mixed into each pattern is often a more unusual move that will be new to you. Just like all good turn patterns in class should be: easier moves in new variations, and one or two difficult ones that make you scratch your head at first.
One thing I was tickled by was seeing a few pet moves I might have discovered independently on the dance floor or from horsing around with my girl friends are actually in the video. Now hundreds of other people will know them too... sigh...
All Absolutely Leadable
All his turn patterns are leadable with a lady of intermediate to advanced level, although some such as spins obviously require someone competent in that. Still you can change them round from doubles or triples to singles for lesser spinners, and the essence of the pattern will still be there.
The only exception is in Vol 4 and 5, where Mario gives you a pattern that he specifies is better for choreo. Even so I've tried them out and they are also leadable but probably best reserved for an advanced salsera who will be faster to react. At least he specifies what is a choreo move so you're never going to try something beyond your skill level to lead.
Generally Superbly Detailed
I really love the way Mario breaks his patterns down. I've reviewed elsewhere that some of the DVDs, notably Salsafreak and Liquid Silver's old Advanced DVD, glossed over too many essentials, especially their next to useless breakdown of the Men's Tunnel. NOT so with Mario and Susana.
The only objections I have are that some moves that are explained in perhaps too much detail, such as a simple half coke, take away from what I feel deserve more explanation. That being said, Mario glosses over nothing. He discusses body positioning, hand hold switches, subtle differences in common moves, etc that makes an unusual move work.
For example I believe it's move turn pattern number 4 or 5 of Volume 3, he spends a fair bit of time explaining what is a rather simple hand switch, but doesn't break down is so much detail the move following this, which an unusual crossed hand hold copa -> simultaneous FO and LE combination. I had to experiment quite a bit before getting it.
Summary
Buy. Even the Volume 1 with simpler patterns is worth it for revision of fundamental footwork. My only advice is the same one I give to all beginners: a DVD is best used for an intermediate social dancer with the experience to understand what is being explained, along with what may not be, such as body positioning and set up of relative facings, etc in order to make a move work without hurting the lady. Beginners, and other people from 'higher' levels who only take classes but don't social, should not learn from DVDs without access to a live competent instructor.
I have a lot of DVD and those are my favorite behind salsacrazy series (really fantastic, intermediate vol 2). I am a 5 month beginner and I pick move here and there from the complete routine. There are some move I won't even care about because too hard or need more intimate follower (I guess). For example moves where you need to move follower with hand on stomach