Bulgaria is much safer than Russia with much less violent crime on the streets.
Russia on the other hand is very expensive and not very safe.
Some Russian ladies will be more inclined to seek a foreign husband for the simple reason of being less financially secure.
This does not mean that you can just walk into a Russian marriage - the Russian women are choosy when it comes to men.
Most Bulgarian women on Sesile do look for a husband, but probably 30% seek just chat online and pen pals of their own age from another country and are less likely to be willing to leave their country and settle abroad.
A much larger percentage of Bulgarian women are financially independent compared to their Russian counterparts and are not driven by financially desperate conditions to search for a husband and marriage abroad.
Bulgarian women are less likely to have professional photos; they are more likely to take a few quick snapshots with their web cam.