Yeah, just tried again with my previous save and the Harridan was chewing right through my armor. So I guess armor is meaningless with the Alien Sniper Rifle. Had a look through the weapons_gc.xml file because I was curious about mitigation. The Alien Sniper Rifle does indeed have 99 mitigation, but the Assault Plasma has 10, Heavy Plasma Rifle is 30 and Battle Rifle is also 30. Interestingly, Reaper Claws have an incredible 500 mitigation and my namesake, the Zombie, is 40.
Suppose I should mention another difference in Xeno, Sebillians regenerate health. Duh! But no aliens have this feature in X-COM. On another Carrier mission, one of my "green" snipers was plugging away at a beast from a distance, but it was regenerating about 50-55 health units per turn. Talk about one step forwards and two steps back! I did eventually kill it, but only because there was a building next to it where a few team members could get close to ensure damage. With these aliens you almost certainly need to double (or even triple) team Sebillians.
UFO doors close automatically during the aliens round like in UFO, but now soldiers can open and close them themselves. The benefits to this are immeasurable. Afraid of reaction fire during a retreat? No problem, close the door and then leave. Now you can stage your teams right at the doors instead of around it which saves some TU next turn. Worried you might not have enough TU to shoot an alien and retreat? Here again, have someone else (aka cannon fodder) open the door and now you probably will have enough points leftover to get back behind the door for safety. Aliens normally stay holed up in the command room thinking it's safer to camp than to bum rush the door, so that's another reason why doors are important. The only time you'll have a problem is with Androns (and to a lesser extent, soldiers wearing Predator armor). They will smash through doors like a bull in a china shop so it becomes inoperable (and always open).
Sometimes a door to an alien ship will remain open (Carrier is a prime example) for some reason. If there aren't Androns around, you are pretty safe to assume you can close it again though. I had to do this today actually. For the first time since I started this new campaign, the tank got to sit out in lieu of 2 greenhorns which needed improving. One had pretty low health and firing accuracy, so he had a shield and a plasma pistol while another got a plasma rifle. Now, you would assume that a Shrike dropship having a capacity of 10 soldiers should have a capacity of 6 soldiers and a tank (4 tiles big), but no, it can actually carry 8 soldiers and a tank. (The Xenopedia does mention tanks count as 2 spots, though I never read it carefully). Anyhow, these 2 newbies were in cover just in front of the main door, but I didn't want them to be sitting ducks if they made a dash to it and it couldn't be closed. So I had a soldier with a lot of APs close the door first, then brought in most of my team.
Right now, I'm at that point in the game where I'm torn between weapons and aircraft. My main production base was in the process of constructing my first Marauder aircraft, but I didn't produce enough plasma weaponry to equip the newbies with them. I wanted these guys to get some kills and to do that they need high damage weapons. What I ended up doing was equipping some of my vets with laser weapon equivalents instead, and giving the newbies the plasmas. The rationale being that the vets will make every bullet count due to their higher accuracy, while the newbies would play cleanup. Because they have mediocre accuracy you can only really count on one bullet of a burst connecting so you need higher damage to level the field and ensure a kill. What do you guys think about this? This situation is only temporary as the Marauder is completed and my manufacturing team is now producing a couple plasma rifles and plasma pistol but that takes time. In the other part of the world, my research base is hard at work figuring out MAG weaponry (still only "Good" status so it'll be a while before I get them). I'm almost leaning to constructing another workshop to help the process along.
With all the incoming cashflow from large-massive UFO missions, I built my fourth base in South America. Seems like a good place as the aliens are constantly buzzing around there. I figure I can equip this base with hand-me-down Foxtrots and Corsairs when enough Marauders are built to upgrade my aging fleet. Dumb question, but how many defense batteries are enough to prevent base attacks from getting through? My two main bases have three each because they also have soldiers and tanks to defend, but what about my other non-soldier, non-tank bases? Should they have more than three? (At this time it's plasma defenses but will be MAGs soon enough).
Anyhow, back to the grindstone!