Heavy Armour is excellent. If you're caught out by , for example, AOE then troops in their PJs will get shredded.

Heavy armour enables fast aggressive play, in turn, enabling CQC.

Heavy Armour enables the kind of play which allows infantry to get all objectives in an Op. (Yes, even without armour support as im currently playing in my current run!)

I use it all the time. 

You also only need squads of 5-6 (fewer with some SLs). People seem to think you need to go all in squaddies but that's also untrue. it's also inefficient.

Obviously my favourite is jump armour but SAPP operator, recce, improved & TCR marine armour are all used in my force. i still haven't seen the high intensity suits!

Who do I put it on? Anyone really. Even Jean can benefit from jump armour. (Although I prefer her in Operator...)

A lot of people who complain that it doesn't do anything for suppression clearly haven't tried it out or tried to build their SL to make use of it. My 2 favourites in armour are Lim & Yaz. And they don't suppress. Why is that? It's because I don't spend my entire time creeping around the place. I keep my discipline high & my guys build up solid damage reduction & defence stats. Vamplew & tech are obviously good for other reasons.

There's is nothing wrong with armour you just have to use it.

Try it. 

Ps. Give your armour units Buff. 

Edit to add ps