There are certain facts like the way how enjoying Blockland costs only 20$ and Roblox has a monthly fee + freedom of certain things kind of make the other better, but its all up to you which one you like.
You forgot to mention roblox's stuff playerbase. You tell someone your 17 in a convo, three 9 year olds pipe up HAHA cigarette U HAV NO LIFE GO DIE. Or if someone is spamming chat "GUYZ LOL I HAZ A MONE LOTSA MONE" and you tell them to stop talking, their only response is "NOU"
And then there's killing / fps servers. I swear if someone doesnt call me a hacker once per game per server, I must not be on roblox. Being able to get 13 kills without dying is NOT hacking. It's planting land mines, motions trackers, and using a well balanced weapon. Your just too loving stupid to realize you walk into my wall of bullets.
The game would beat block land, if THAT playerbase died and THIS playerbase took its place. That said, BL has its charms. I still play both, just so I feel bad about myself by the end of the day