Eviscerate does a strong dot.. you could alternate them for max dps. Ravage is powerful because it makes you immune to slows and knockbacks, which would actually be incredibly strong to have higher uptime on armor leech in later levels, where without armor leech stacks you die very fast. I have not maxed ravage, but have a high level eviscerate, and it hits pretty hard. I assume that ravage over the 4 seconds would do more damage. It is now a question if ravage stacks armor leech passive, if not, i wouldnt take it, if it does, i'd probably end up maxing it too.. just not enough skill points for that -.- i did try level 1 ravage but ofc it was so weak i didnt like it.