These are more notices than reviews, letting you know about some of the recent video products ChessBase has released and some quick thoughts about them. Bear in mind that I get these as review copies and work for them, so while I can assert that I'm going to give you my honest impressions about the material, you should at least know that I have a potential conflict of interest. Without further ado...
GM Adrian Mikhalchishin has released a couple of disks in the last couple of months on strategic themes. One is called "Power of Planning" (POP), and the other is "Power of Exchange" (POE). (Alas, "Power of Definite Article" is missing.) Both are about three hours long (the first runs 3:19, the second 3:00), and both are worthwhile for club players. POP divides into two parts. In part 1, he discusses pawn majorities, and in part 2 he discusses weaknesses.
I think the discussion in part 1 is useful if a bit one-sided. In particular, in the well-known structure where one side has a 3-2 queenside majority with an extra c-pawn against the opponent's 4-3 kingside majority with the extra e-pawn, it's the former who always comes out on top in this video. It is certainly important to be familiar with typical ways of exploiting that majority, but it's good to know that the central/kingside majority can win the day too.
That said, I liked part 1, and think part 2 may be even better. There he presents and demonstrates the key to planning, which he describes as a several step process. For him, plans are all based on weaknesses, and he divvies up the planning procedure roughly as follows: identify a (potential) weakness, create and fix it, tie the opponent down to it, create a second weakness and win by stretching the opponent's defense too thin. It's true that one's opponent sometimes fails to cooperate with this schema or - even worse - apply it to us - but even it's a useful schema.
Next, there's POE, which also comprises two parts. Part 1 runs through a slew of Rubinstein games, demonstrating his very impressive technique in forcing and exploiting favorable exchanges. In part two, Mikhalchishin discusses bishops and knights, generally focusing on situations where one side has a favorable knight vs. bishop imbalance. Needless to say (but I'll say it anyhow) such a work is far from comprehensive, but what is there will benefit many club players.
Should you buy them? That I can't say. These aren't must-buys, so you'll have to decide if you think it's a worthwhile use of your own money. I do think they offer useful concepts for club players, and the examples are well-chosen too. If I had to pick one, it would be POP, and there's an important reason for this. In many works on positional play, a concept will be noted and examples provided, but you don't get much guidance on how to use it in the different situations you'll get in your own games. It's all autopsy and no preventive care. The strength of POP is that if offers advice you can use almost immediately, so to speak in Ebertese my thumb is closer to "way up" than it is for POE.