You probably meant this question to be answered by foreigners, but still I venture to express my opinion.
The thing I like most about Russian is flexible word order. Such flexibility and freedom give many opportunities for expression, choice and variety.
Also I think Russian is an emotional laguage. I like all these numerous suffixes: -ик, -чик, -ка, -ище at alias.
And you, Marcus, I suppose, there is something you like about Russian, isn't it.