BMD

The BMDs were a series of Soviet Airborne IFVs, something which to this day is a relatively unique concept. As such, they don't really have a counterpart in the armies of NATO.

BMD-1

The lighter, airborne brother of the BMP-1, the BMD-1 somehow manages to fit the exact same turret with the exact same weapon systems as its heavier brother in the regular army. This means that it fills a very similar role, and its primary differences are in training and organization. The BMD comes in smaller unit sizes than its heavier brother, as BMD companies don't come with PKMs by default and rely on the more spacious BTR-D when they are taken. This doesn't mean that you can't bring a sizeable number of these though: the basic company still goes up to 10 BMD-1s, a solid hunk of gopnik steel.

BMD formations are part of the VDV and thus represent better skilled, more motivated troops. This means your BMDs and their riders get the coveted skill 4+, a rare commodity in the Soviet arsenal. This lets you perform movement orders more reliably, which gives you more options to use your missiles, as well as letting you range in the 2 arty in the Soviet arsenal with a 4+ skill on a 4+. Really the ability to more reliably perform movement orders is the big change here.

The Afghansty VDV platoon also makes use of the BMD-1. Everything above still applies, only more so. They Afghansty VDV come in companies made up of platoons with but a paltry 3 IFVs each. However, they are relatively inexpensive for their stats, and they have an even better 3+ skill, letting them use movement orders even more reliably.

For the BMD-1 itself? It's a pretty solid little tonk. Its real strength is the large amount of good firepower shots that it can bring for the points, with both an AT19 missile and an AT12 low velocity 73mm cannon. Both of these are HEAT, meaning this thing is particularly vulnerable to special rules that boost side armor to HEAT weapons, particularly Chobham or ERA. Against vehicles with light or even medium armor, however, your weaponry is relatively capable, instantly penetrating most APCs, IFVs, and other support vehicles while killing on a 3+. Your missile won't hurt the Abrams or other 3rd gen MBTs, but it'll kill the shit out of 2nd gen MBTs. Consider bringing some form of heavy AT to back these things up.

The armor and mobility are meh at best. You will not be saving from anything with a half decent AT rating, and with a 3+ to hit (4+ for Afghansty VDV!) expect to lose a lot of dudes if your opponent gets tired of them. This isn't helped by your poor 4+ cross check, which limits your ability to use woods and fences to the fullest. Try to stick to ridgelines or conveniently placed vehicle wrecks for cover. As a consolation prize, you get among the highest tracked dash speeds in the game, a blistering 36" on road, if you'll ever need it.

BMD-2

The airborne version of the BMP-2. Has the same 2A42 30mm autocannon and Konkurs missile on a modified BMD-1 turret, so once again, just expect it to be a (potentially faster) lighter armored version of the BMP-2 with a lower transport capacity. The more interesting changes are going to be to the unit sizes and training.