Pretty right? Here's the older one for comparison.
The newer wallpaper is definitely cleaner, more professional looking with better colors. I won't bother tinkering with wallpapers anymore, the new default on Ubuntu 19.04 is just perfect.
Too funky for my taste. But I'm sure there will be many who will prefer this darker, edgier, wallpaper over the others. As we said earlier, the new "disco dingo" mascot calls for infinite wallpaper variations.
Apart from theme and artwork updates, Ubuntu 19.04 has the latest Linux Kernel version 5.0 (5.0.0.8 to be precise). You can read more about Ubuntu 19.04 features and updates here.
Ubuntu 19.04 hit beta a few days ago. Though it is a pretty stable release already for a beta, I'd recommend to wait for another 15 days or so until the final release. If all you care are the wallpapers, you can download the new Ubuntu 19.04 wallpapers here. It's a DEB file, just do a double click post download.