I agree with some of the points made about it needing a bit of tweaking. But overall, I think the consensus that is emerging in this thread is that it is pretty damn cool, it isn't grossly overpowered (powered yes, but as I said it has significant constraints), but could use a bit of 'balancing' on the stats.
I think that the following might be good changes:
1. Increase the steel required to fix it to anywhere from 4 to 10. Right now, even if it is completely 'broken' it takes only 4 steel, and perhaps some other components. Making it more expensive to fix it might be good balance. One point of note here, it seems that, if it is only slightly damaged it costs 4 steel to fix it, if it is totally damaged it seems to only cost 4 steel, plus (in some cases) other components. I think a minimum of 4 steel is fine, but maybe make it cost more to fix it when it is damaged. Increasing the perk requirements might be good too.
2. It would be nice if fusion cores were more scarce and more expensive to purchase (I've bought them for as little as 500 caps) but I don't think this is a change Beth would find it easy to make in a patch. Perhaps multiplying the cost of fusion cores in the game data by 2 or 3 times might be easy to do in a patch. That way, it makes using it more costly and actually 'balances' out the benefits of not using it: if you do not use it, then you can just scrap all the sets you find and sell the fusion cores! Make a lot of caps!
3. I agree it is inconsistent (both with lore and with the logic of it being "nuclear powered") that it expends fusion cores . . . but without this it really would be overpowered. You put it on and it never needs to be fueled up and all you have to do is keep repairing it? That would be OP. Being able to absorb that much damage really must come at some substantial costs else it really would be OP as some have said.
4. Increase the basic load bearing benefit pretty substantially . . . maybe just make it 750 without any mods? At strength 6 my toon can carry nearly 300 so it would seem to make sense that the suit would allow you to carry at least more than twice that much. No?
Those seem like reasonable tweaks to make it a little less powerful and thus reduce the risk that it really is OP. I have to say though, you folks who think it is OP, have you really used it?
I now have about 6 or 7 settlements, and I scrap nearly EVERYTHING. I definitely scrap every single car wreck, collapsed building, tree stump, etc. in my settlements when I first get them. So I've not been the least bit lax about scrapping to get steel. I was holding off on scrapping a bunch of weapons until I got all the Scrapper perks, but recently gave in and scrapped a bunch of weapons with only Scrapper 1. I still have a couple levels to get scrapper 2.
I have used the suit during one maybe two play sessions. I upgraded a T-45 to model B, and I have repaired it a couple times. So I haven't really used it that much. I have also built a LOT of structures for my settlements (probably too many ) and made a lot of weapon mods: I'm a hoarder and a crafter at heart and I'll never pass up "free XP."
With all those factors in mind: I keep running out of steel and am having to do runs to loot raider lairs in order to get hold of enough steel to make beds and stuff like that. In sum, it is possible for steel to be a scarce commodity depending on how you play, so if you are going to use PA all the time, you are probably going to have to keep that factor in mind and that alone makes it "not OP" I contend.
Even for a character that is a sneaky sniper or other form (which mine is) I think it does have it's place. There are problems to be solved where sneaking and sniping, etc., are not useful and where high rad resistance and damage resistance are the best solution. The PA is really useful for those contexts.