Everyone has their own subjective opinion.
I frankly loved Bozja WAY more then Eureka. I didnt need to beg people for help and get ignored and waste hours of my life to play catchup on my ALT in Bozja.
Meanwhile, when Eureka came out I had to work for a week straight and start it later...when I had free time to start, everyone was max level and farming High Level NM Trains, nobody wanted to help out noobs that came in late. Getting Exp was WAY to slow, some people said powerlevel by joining the trains and getting minimum rewards...which helped, but still took forever because you get next to nothing from level descrepency. Then I got deleveled when trying to get to an area and got 2 shoted by an enemy...and people just ran past me even when I called out my location for a rez.

So many will tell me how great Eureka was, and I envy all of you can say that, because my experience was nothing but pain. Im lucky that years layer and after the completion of Bozja, so many have downtime and have gone back to Eureka. Things are nerfed, things are buffed, gains are better, and the community seems way more n00b friendly and more people are willing to help.
So I finally got through it.
I just hate it took about 4 years...