I definitely will get it, since I've been participating in the Technical Preview since it became public. From what I've discovered, it's basically Windows 7 with a smarter Windows Menu and overhauls to speed and responsiveness, and of course, graphics. Certainly won't top OS X Yosemite and El Capitan in my book, but it's a start towards a brighter future for Microsoft.
Another reason I was so excited for Windows 10 was Xbox One and PC Crossplay (Which should have been a thing way back to the 360). However, that's minor compared to the Hololens. I have high-hopes for this thing, and if Microsoft manages to somehow screw it up, I will probably lose faith in them for eternity. I also hate how their acquisition of Mojang has almost been used as an advertisement as-well. They featured Minecraft in Hololens, and even Windows 10 (I mean, why did they need to make a sole version to run side by side with pocket edition? Just let the PC version and Mobile version overlap, so another whole version is released.
Well... That got a bit off topic, and a bit rant-like, but I enjoy Windows 10 none-the-less, and encourage people to upgrade.
EDIT: And Terraria and other games appear to run just fine on it. No reason for them not too, unless Microsoft for some reason drops the rest of the .NET framework like they did XNA