This is a huge one.  Heavy armor, as its name might imply, weighs a lot and slows you down noticeably.  Removing both of these impacts from it is worth a great deal, and having a perk that provides that makes up in every possible way for the low value of Fists of Steel.  Even if you find that both Fists of Steel and Cushioned have no value to you, Conditioning is so strong that you probably won’t mind.  If, for whatever reason, you consider three perks too much to pay for this, then you could instead go find the Steed Stone, but spending your Stone effect just to offset your choice of heavy armor is a bit silly when you could drop three of your eventually seventy-nine perks to do the same and have an always-useful Standing Stone effect.  If you’re having trouble carrying things, you can always foist them off on your follower, and if you can’t carry all your stuff with you at once, well that’s what you can get a home for.  Breezehome is pretty affordable and comes with plenty of containers, and there is a home available in each of the other hold capitals, as well as a very large number both with and without free resources can be found if you look for mods on Steam or Nexus.

Matching Set-

While getting the necessary pieces to have a complete set of matched armor is difficult when you’re relying on finding armor in dungeons, anyone with Smithing will have what they need to grant the benefit of Matching Set all the time.  Generally speaking, having Matching Set means you won’t want to put on new armor pieces until you have the full set of armor, which isn’t too much of a problem to do in the lategame when you get this perk.

Reflect Blows-

If you wear heavy armor, you want this.  10% may not seem like much, but if you’re wearing heavy armor that probably means you’re getting in long fights and turning one blow in ten that lands on you into an automatic strikeback can give you a huge edge in battles, particularly when fighting a giant or a dragon that’s landed in melee range in one of the drawn-out slugfests that such fights generally become.  This is especially nice for heavy armor mages, who can consider this an added punishment for melee enemies or alternately a way to make close combat that much faster and safer.