One of the key aspects of Flames of War, and in fact many wargames, is the random element. Many actions do not have an automatic chance of success, and instead success or failure is determined by one or more die rolls. Generally these rolls will have a target number that must be matched or beaten to achieve a success for the action. In an ideal world, the dice used in wargaming should be truly random. In other words, for any given roll you should have an equal chance of rolling any of the possible numbers on the die, sometimes called "equal access" to each face of the die.
Unfortunately most dice used in wargaming fall fairly short of that mark. Most dice are manufactured using a process that creates recesses in the faces for the markings, are then painted, and then all of the dice are polished back to leave the paint only in the recesses of the designs themselves. This process results in very attractive dice at a reasonable price point, but it also results in dice that are not perfectly cubical (in the case of six-sided dice) or perfect polyhedral solids (in the case of other dice varieties). These imperfections result in dice that will tend to roll some numbers with slightly greater frequency than others, even in the absence of manipulation of the dice themselves.
This fact explains why people can legitimately claim to have "lucky dice" or "unlucky dice." In this case it really isn't superstition. If you roll the dice enough, you'll get a feel for which ones tend to "roll better" (i.e. will favor one or more high value faces). My problem with this is that anyone with a "blessed" set of dice is going to have a slight advantage in any game. Conversely someone who has pulled a new set of dice out only to discover they're weighted in the opposite direction is going to have an unfair disadvantage.
So what alternatives are there out there? Casino dice are precision manufactured to strict tolerances by law, and do give equal access to each face on the die. Unfortunately they are also very large and have to be "thrown" (usually against some sort of backstop) to function properly. This is generally not going to be practical or even desirable for a tabletop wargame. Other people advocate use of computer software to generate random numbers, and while some of these may get close to statistical randomness, short of advanced (and usually expensive and/or proprietary) computational based models, the best most people will be able to get with a computer, tablet, or smart-phone is a pseudo-random number.
Based on my experience there are at least a couple of precision dice products out there that meet all the criteria to generate truly random numbers for Flames of War. The first would be Gamescience dice. These are precision dice available in a variety of types (you'll only need six-sided dice for Flames of War, but they have broader polyhedral types available). They are going to be more expensive than Chessex dice, (~$2-$3 per die for six-sided dice), but they are precision crafted. In some cases you'll have to ink the faces to make them easier to see. I own a set of red and green dice I use for Flames of War tournaments, and I've never felt like I lost a game because the dice weren't truly random (not saying I still don't roll a "1" at the most inopportune moments!). Unfortunately Gamescience appears to be in an ownership / production transition at this point, though the Dice Shop in the UK appears to still have a strong inventory.
Though Gamescience dice are very good, they do have a few drawbacks. The dice are not polished, so they'll frequently have a mark where they are removed from the sprue. Some people try and sand the area, though I generally don't as the whole reason I purchased the dice in the first place was to avoid sanded or polished dice. Gamescience dice also have the knife edged profile in common with casino dice, and though they are much smaller, they may not roll well on a hard, slick surface once again defeating the purpose of using a precision die!
An alternative that the gaming community is starting to experiment with is the use of precision backgammon dice. Precision backgammon dice combine the pure randomness of casino dice or Gamescience dice with the rounded profile of the more familiar Chessex style dice. If you look at a precision backgammon die, the overall shape is cubical, but the faces are actually all perfect circles. The rounded corners make the dice easier to roll in tight spaces allowing more tumbling for a truly random result. There are a few drawbacks, however. Backgammon dice only come in a d6, which is fine for Flames of War, but completely useless for systems using other types of polyhedral dice. They are also much more expensive, with prices starting at ~$5 to $7.50 per die.
At this point I've picked up a few precision backgammon dice that I'm going to try out at my next tournament. As a gamer, my goal is to use dice on the table that I would actually want my opponent to use as well because I'm convinced that they are 100% fair. Ideally, I want the game to be decided on the merits of the tactics used, but given the element of chance to the game, luck will frequently play a role. If the game hinges on the luck of a die roll, I want that die roll to be truly random, not the product of a "lucky" or "unlucky" sub-standard die.