I do not think I had ever used Power Armor in any previous Fallout before this one. So it didn't really bug me that it is so 'readily' available [no spoilers in this thread please]
Having now messed with it a bit, I find it is a somewhat mixed bag.
The good:
1. You can go up against a lot of baddies at once and survive without too much use of VATs, Chems, etc. Basically you "spend" steel instead of other stuff.
2. Increased carry weight.
3. Radiation, ha!
4. Falling with no risk = nice in some circumstances.
The bad:
1. If you jog, and do not use fast travel, it is extremely boring to slowly plod across the wasteland. I believe I will suspend my Skyrim conviction to "not use fast travel" on the grounds that it diminishes full enjoyment of the game, at lest whenever I'm wearing power armor.
2. Even when you do not use VATs, jog, sprint or do any of the stuff listed in the Help as depleting your fusion core, it nonetheless seems to deplete slowly just from wearing it and walking around . . . or so it seems to me. I just built a settlement not too far from spawn, and my power level definitely dropped a few points despite never running or sprinting or taking any damage.
3. Sneaking is obviously impeded, and peripheral vision seems slightly worsened.
So is it just me or have other folks noticed that your fusion core depletes even when you only walk around? Does absorbing rads or damage reduce the fusion core power supply?