Both are great products with excellent protection. I really don't think you can go wrong with either one. I haven't tried F-Secure in a while, but from what I have heard/read since switching to the Avira engine, it seems like they have made some great improvements. They have Deepguard, but Eset has HIPS. Eset is a tweaker's dream. Both are very light weight, so really I think both will serve you well. I would trial both and see which one you like more. Last time I tried F-secure, I couldn't get over that baby blue colour they have on their UI. I wish it was a more darker blue as I find that light blue makes it look like a kid's toy. That's just personal preference, but it drove me crazy lol.