the 2nd ("Avantgarde") has some aoe knockdown skill and there comes some item which restores your HP once the suit is destroyed (teal handbook)
(what i dont know if we can use the teal handbook on the monolith too or not)
Last chance
After the destruction of the armor assault carrier to heal 1000000 Health.
Skill is acquired after reading Newest inventor directory.
the 3rd ("Escalade") also has some protection skill :
Cover
If within 10 seconds after activation of this function, your target is below 30%, it receives the effect of "Secure Fence", which is 4 seconds Reduces all damage taken by 90%.
maybe the total HP of the newer suits are also higher, i dont know
but for everyone who does not have one this is recommended i would say while getting another one when you have the 1st one already is very questionable as you (sadly

) cant wear them over each other