I don’t like stealth games much. What I particularly don’t like about them is the abrupt instant-fail nature of stealth games. I loved the original Deus Ex, but I wasn’t terribly sneaky in that game. I was hoping for something of the same experience, but I feel the game strongly rewards stealth, and it’s difficult for me to deliberately avoid what appears to be the best path.
That said, the other things I don’t like about DXHR as well. I don’t like the random nature of the hack failures, though with Capture 5 / Hack Stealth 3 that’s largely under control. And I’ve already detailed what I don’t like about the conversation system.
As for Fallout: New Vegas, I really liked that game. Maybe you’re confusing the things I disliked about Dead Money with the game as a whole?
EDIT: By the way, thanks for making clear you were asking a honest question. The acidic nature of the internet (and of this forum on occasion) can easily make such a question sound like “learn2play” when you’re honestly wondering if it’s a matter of taste.
Chris has the right of it. The correct way to use energy is to have 1 bar most of the time. You can do any action that takes 1 bar of energy as many times as you like, since that 1 bar always replenishes. You should only use consumable energy regeneration if you must use multiple bars, or you need energy right now and haven’t recharged yet.
Most of the time, 1 bar is enough. 1 bar is a takedown, or a sprint from cover to cover while invisible. At Cloak-3, it’s 7 seconds of invisibility, which will almost always let you reach where you want to go. Candy is for special situations that require 2 or more bars, like running up to someone while invisible to do a takedown, because there’s no cover and no way to bypass them.
It’s worth noting that the last bar regenerates if partially used, so if you’ve eaten a 3-energy jar, and thus have 4 bars, you can use the Vision power to look through walls, turn it off, and then wait a bit for the last bar to recharge. Similarly, if you use Cloak, if you don’t use a full bar, you can regenerate it.