General Annoyance wrote:
Each Mark of armour has its own set of strengths and weaknesses, but most of the time you'll see Space Marine wearing different pieces from different Marks because the full suit was lost a long time ago.

Errant armour is a slightly different story as it is being made in current 40k times along with MkVII Aquila armour. Its protective capabilities are among the best any Mark of Power Armour has to offer, however most helmets from previous Marks are incompatible with it thanks to the neck guard protecting the cabling and actual neck of the Marine wearing it.

 jhe90 wrote:
Blood Angels or Salamanders bring no plain Armour though,

Crafting/forging is big in there cultures

I am just wondering what people thought as far as some reasons they might defer wearing the deathwatch's armour.

Aedgar Perri wrote:

I am just wondering what people thought as far as some reasons they might defer wearing the deathwatch's armour.

to answer; they do it for Martial pride. In most Chapters certain marks of armor carry special significance( i.e. Mk VI Corvus to the Ravenguard). Also, it's usually the power armor that a Marine was issued once he was promoted from the Scouts, it's a suit he's worn for decades or even centuries of warfare, it's probably a relic of the chapter which has been worn by great warriors for generations possibly dating back to the founding of the Chapter. Would you give it up for a fancy new suit fresh off the conveyor belt from Mars?

Also a consistent theme in the 40K universe is that new tech isn't as good as the old stuff, I'm sure that Astartes are the exception but still something to think about.