Board Thread:Questions and Answers/@comment-25596947-20141114200918/@comment-200.114.179.44-20150227232800

"Each point added to Swiftness increases attack speed by ~0.015 at the early stages. Every consecutive point allocated to the Swiftness attribute increases the Heros attack speed by a higher value. Therefore investing points into this stat starts to be beneficial for your dps at higher stages while flat damage from Strength has a higher effect on your dps early on. But since the main damage your Hero deals usually comes from his skills which scale with your flat damage it's more beneficial to increase the Strength Attribute in the first place after all to accomplish success."

I guess that in the marksman case the best way to lvl would be  the following: until you are lvl ~15 would be to lvl fully dmg, then until you are lvl ~25 to allocate 1 dmg and 1 spd and then to fully allocate speed.