Quite a few of WH40K's troop types/races are described as wearing power armour.
Space Marines are the most obvious. I get the impression SM's are decanted from
their birth flask into power armmoured romper suits and stay in them until
they're recycled for spare parts.
There's no demob suit in the Space Marines!

SM's also have Terminator Suits. These appear a lot more powerful than the
standard womble suit.

But the Eldar and Tau also appear to be wearing something described as power
armour.

Eldar suits appear rather more elegant than SM's. Is it just better technology
or is there a difference in protection offered ?

Tau battle suits might be better described as one-Tau vehicles (along with
dreadnought armour).

Are there different grades of 'Power Armour' within WH40K ?

It looks as if we might be providing stats for Power Armour suits rather than
for troops...

Chris