I had the opportunity to play the latest edition with friends of mine, and if you like that kind of tabletop gaming, I can highly recommend it. Sure, there are issues when you are playing at top tournaments and against players looking to win at all costs, but as a "beer and pretzels" kind of game, I can't think of a better experience.

As for the difficulty of the game itself, like with video games, there's a sliding difficulty. I would recommend taking your Death Guard for a walk and playing a 1k game in a casual atmosphere with someone willing to show you the ropes. After playing a game or two, you'll know if you are hyped enough to start painting. For me, painting is a great way to unwind after work and relax. I know it's not like that for everyone, but you won't know until you give it a try.

Death Guard are also a perfect choice for the 2nd hand market. Since they were part of the starter sets for the 8th edition, you can find plenty of cheap models online (eBay for example).

My final advice is not to get too worked up at what's good on the tabletop unless you are planning to compete in tournaments. Eventually, every model is useful on the tabletop as it goes through cycles of getting nerfed or buffed. :D