I tried both not a long time ago and my results where similar.
Both are good as far protection but a few days both gave slow down in browsing.
But i have to say that my laptop is 6 years old so i don't find these result so strange.
Someone who has a newer/better system i don't believe that he/she will notice slowdown's.
If i have to choose, tough choice, it would be BD not for detection because Dr.Web also has good detection but
for the Active Virus Control component which offers better 0 day protection now for BD.
But this is just my opinion