There was an interesting question
recently, regarding what is the difference mentioned on this topic's subject.
My opinion can be considered only as a subjective one, like anyone's opinion on these forums; however regarding my own experience, there difference between Russian girls living / born in Latvia, and "pure" Latvian girls is obvious, despite they form the "common" look of the Latvian women population in general.
Most of the prostitutes or girls involved in scam business belong to Russian girls. There is also a lot of similarities between Russian girls, let's say, living in Riga and Moscow, many of them wearing the same dress, having the same tastes in fashion, music, pop culture etc. Actually, Russians living in Latvia are not gifted by government, that's why they may feel there is no real "native land" for them here.
"Pure" Latvian girls belong to some kind of alternative thinking, they have another level of education and the feeling of life, specially family life. They do not like foreigners, and may be only girls from the Latvian districts are going to the capital to work for prostitute or striptease dancer.
I must say Russian girls in some cases may look more pretty than Latvians, that way their "slavic" roots come in place. Latvian roots go to Germans and Scandinavians.