Well, even from a technical standpoint, Blockland is pretty impressive.
I mean, you can host servers with several people with up to around 50,000 bricks before you start lagging (depends on connection).
Granted, Kompressor helped a bit with the oct-tree 'thing' that helps hides bricks out of sight.
On a side note, several pages back, Tails mentioned that "most can build without thinking about it" and was referring to the BL brick-placing control scheme. Now that I think about...I never really do think about how I am pressing each individual key...you just get used to it.
Roblox's brick placement seemed a lot more.... picky. Rotating your bricks and trying to squeeze them in was rather difficult.
It does seem wrong for Roblox to start selling off merchandise for a game thats, as you said, "Deep deep in its alpha stages".
We each have our own games. Lets leave it at that. =)