The current K12 line and design is pretty old right now - that said, they still work fine. Quite a few here have used (at least at some point), something from the K series. I use the K12.1's still when I need to. Currently, my mains are EV but I also run QSC and Peavey.
I'm a huge fan of the K-Series. I was probably among the first DJs to ever use a set (months before they were on sale to the public). It is a great speaker line that still sells incredibly well. A lot of rental companies use them. That said, their feature list is falling behind. Many newer speakers have built-in mixers that can be controlled via BT. That was a key reason I just purchased a JBL Eon Compact. A K.8 is similarly priced, much louder and sounds better but I wanted the extra portability and mixer features of the JBL.
I think I gave my opinion on your other thread regarding QSCs. They're great speakers but for the money, I'd go Alto TS312s. 1/3 the cost and they perform very much the same as the QSCs. Now that said, if I were buying for mobile work, The Evolves would likely be my box. The sound is great and the subs are more than adequate.
In my opinion, what matters most is what you like. Look for speakers that have the features you want.
For me, the best possible sound that’s very portable is very important to me, as I’m moving these things a lot.
Reliability is very important too. This includes being able to get something fixed quickly.
In my experience, life got easier when I stopped buying cheaper speakers. Higher end speakers don’t break down nearly as much, last much longer, and have a much better resale value.
For some, they want one kind of speaker that can do everything. I prefer different sizes so I can bring a 14lb speaker that can do a retail store, backyard party, ceremony, or other light duty. Then another that can do a party for 250.
For some, that’s crazy. For me, lugging 60lbs speakers for a ceremony is crazy.