I know it's a lot to take in, but... what part of the update are you on the fence about? I'd assume the storefront, but hey, I've been wrong before.
The new items range between "mostly useless" (Sydney Sleeper seems this way - no headshots, and applies Jarate only on 50%+ charged hits...) to "OMG THIS IS AWESOME!!1" (Short Stop. 4-barreled, long-range shotgun - it'd be epic even if it didn't slow people!), with most of them at least mostly awesome.
The hats are a pain in the rear, but apparently crafting recipes will be released sooner or later for them. (Or so I've heard.) Until then, yeah, you basically have to buy the item set bonuses.
The store is debatable. You can acquire nearly every item in there from random drops, and trading means that it's easier to get the random drops you need (not to mention that trading frequently seems to trigger more random drops for the participants!). Honestly, the prices are ridiculous - one new hat costs almost as much as TF2 does when it's not on sale! On the flip side, I've definitely gotten more than $10 worth of enjoyment from TF2, so I'm not adverse to paying them more money (unlike those other FPSes that charge full-price for the game and then demand that you buy DLC to keep up). And the fact that some of the money goes to the weapon designers is excellent; not only are good artists rewarded for their work, it's also an encouragement for more highly-skilled amateur modelers to submit more high-quality weapons.