I've played it. Then, after years of it, I found Minecraft on the ROBLOX forums. (Not even allowed to post about other block games there )
Then I started playing MC. Then I realized how bad the ROBLOX community was. And how greedy the mods were. And that Telamon said that free players leaving helps the game, although free players = about 60% of the players I would think. That, kids, is why roblox is garbage. But thats just my opinion. Although some of the games are pretty good. It's just the community and some moderators that suck.
I have played Roblox. In fact, I'm still active on Roblox and I expressed my love for Minecraft in Roblox. Because I'm a fan of both, I even made a place inspired from Minecraft with working hunger and experience bar.