Yeah, well, while it works pretty much as advertised, if you really want great sound you'd still be better served shelling out for a good sound bar or, what I do, run the TV through your main audio system.
Well, I usually do that, but in my home theatre the audio equipment rack is to the right of the TV and the LG's inputs are on the left of the rear panel – so my optical audio cable wouldn't reach. Not a big deal if I were keeping the TV: just get a new cable – but in this case I had to use the TV's built in speakers for my Roku and Amazon Fire, where they worked fine but left me missing my 250 watts per channel amp.
Fortunately, my 4K disc player patches directly into the audio stack (I use analogue cables for that) and its HDMI stretches far enough to reach the LG. This was the cat's meow!
The G5 uses webOS 24, and its interface is reasonably straightforward – though with so much stuff and so many "helpful hint thingies" that it's more than a tad busy. But if you don't have a streaming device such as the Roku, Amazon or whatever, you can access a huge library of streaming stuff and various apps.
The TV also does Google Assistant, Amazon Alexa, Apple AirPlay 2, and HomeKit. I hate these things – heck, I'd be happy if my OLED TV was just a monitor and offered no speakers, apps, or whatever.
I do like to stream from my phone or tablet sometimes, however.
Navigating the home screen is done via LG's Magic Remote, which I really didn't care for much. The remote is okay, though since there's no backlighting on it, it can be hard to see what button is what when you're watching in a darkened room. I also hated the "Wii-like" feature where you aim the remote at the screen and virtually drag a cursor around it to whatever icon you're seeking. It's fussy and annoying.
Apparently, you can use the remote conventionally, too, scrolling around the screen via its own buttons, but I didn't learn this in time to try it before I had to pack the TV back up. Duh.