My biggest "Wow"-Moments was the world/details of Ghost of Tsushima.
The PS5-Controller with Astro Bot is very cool. The PS5-load times are fantastic and many wonderful PS4-Games looks better on PS5 too.
Demon Souls Remake is impressive too, by Bluepoint Games :)

I was also positively surprised by the PS+ Extra/Premium catalog, especially because of the scope and the PS1/PSP/PS2 games (Rogue Galaxy by Level 5/Ni No Kuni-Developers, Jeanne D'Arc & Everybodys Tennis :D

The 3D pulse headset is pretty WOW. I suppose it'd be more mind-blowing had I not experienced this with Dolby atmos already and in VR games but it's great audio for the price. Best I've had since I had a €250 headset a few years ago and way, way more comfortable. Probably better than Dolby atmos too and definitely better than VR games.

Same, I was surprised that I had 300 euro worth of high quality games that I had on my shopping list anyway on PS+ Catalogue, got Rift apart , Demon souls, Returnal, Tlou pt 1 and a few others. Thing basically paid for itself, if I'd known I'd have upgraded sooner. Sony need to market that better. 

Now with the ps5 user base eclipsing the ps4 base and millions more to come over the holiday and an excellent 2025 promised I can see this generation taking off. Just need those first part titles to come on in, hopefully Ghost of Yotei will be the start of a steady stream of goodness.