Yep. It happened. I reserved one the day it was announced, and on Monday, I finally had it in my hands.
It's been a few days now, so I figured now is as good a time as any to post my initial impressions.
(As a general note here: I'm talking about my personal experiences with the device, and as such, I won't be mentioning hardware specs in any amount of detail; if you want those, go read the official tech specs from Valve.)
The Steam Deck definitely lives up to all the hype in terms of raw power. I tested a variety of games on it, ranging from simple indie titles like Shovel Knight, Hollow Knight, Brawlhalla, and Castle Crashers, to massive Triple A franchises such as Splitgate, Rocket League, Aliens: Fireteam Elite, and Apex Legends, and all were able to manage just over 720p @ 60fps (the Steam Deck's native resolution is 1280 x 800).
This thing is built to last. They spared no expense in terms of the quality of the physical components. The Steam Deck feels as well-made as any other name-brand piece of consumer electronics (okay fine, you want me to compare it to the Nintendo Switch? Fine. It's just as well made as the Switch. There. Done. No more Switch comparisons after this.). The buttons on the Steam Deck have a satisfying click to them, the analog sticks are nice and responsive, and the haptics on the touch screen and dual touchpads are STRONG (but thankfully tuneable).
This is the killer app. Valve have gone out of their way to make a point of differentiating themselves from any other consumer hardware maker in ANY market even TANGIENTIALLY connected to the Steam Deck by making this thing as hackable as possible. Whether it's the built in Desktop Mode (which, by the way, is very cool), or the fact that you can buy replacement part kits directly from Valve, along with helpful guides on how to replace those parts, or even support for wiping the device's OS clean off and replacing it with Windows, Valve is proving that they not only support Right-to-Repair, but that they truly understand the sort of folks who would be fascinated enough by the Steam Deck to actually buy one.