Arkangelus
Prince
I haven't really seen anyone mention this, besides some off hand comments about how people never build them... well, you should! They're pretty much must have for me now in certain places.
First off, the 20HP heal is PASSIVE, meaning you can move, shoot or do whatever you like, and it'll heal your nearby units. Seeing as they'll always been in your territory too, you can move something badly wounded back next to one, then fortify up and it'll heal 60HP over the two turns, meaning you can get things back out to the front lightning fast.
The best use for them though is that they don't just affect military units... they affect civilians, and, most importantly... air units too. Considering that quite a few of the air units have perks that give bonuses at full health, this essentially gives them an upgraded Air Repair heal every turn, so that you can take up to 20HP damage on a sortie and by the next turn be back to full again. Plus since they're inside a city - that's a huge 70HP healed if you do nothing next turn!
I now always build them adjacent to my frontline cities for the fantastic military benefits, and their yield isn't even that shabby either. 2E and later, 1S will only be a tiny bit less than a regular generator, so it doesn't even rule out the use of the tile for the city. The tech that unlocks them also gives the Master Control, which AIs don't tend to beeline for, so a slightly unusual early path can give a lot of support to both city defence and infrastructure that pays off the entire rest of the game.
First off, the 20HP heal is PASSIVE, meaning you can move, shoot or do whatever you like, and it'll heal your nearby units. Seeing as they'll always been in your territory too, you can move something badly wounded back next to one, then fortify up and it'll heal 60HP over the two turns, meaning you can get things back out to the front lightning fast.
The best use for them though is that they don't just affect military units... they affect civilians, and, most importantly... air units too. Considering that quite a few of the air units have perks that give bonuses at full health, this essentially gives them an upgraded Air Repair heal every turn, so that you can take up to 20HP damage on a sortie and by the next turn be back to full again. Plus since they're inside a city - that's a huge 70HP healed if you do nothing next turn!
I now always build them adjacent to my frontline cities for the fantastic military benefits, and their yield isn't even that shabby either. 2E and later, 1S will only be a tiny bit less than a regular generator, so it doesn't even rule out the use of the tile for the city. The tech that unlocks them also gives the Master Control, which AIs don't tend to beeline for, so a slightly unusual early path can give a lot of support to both city defence and infrastructure that pays off the entire rest of the game.