I am user of l2.net and I'm satisfied, but I was user of l2walker as well.
If I had to compare them it would look like this:
L2.Net sure is complicated, you need to spend quite much time to make friends with L2.net, cause it's not so easy to setup. What I don't like about L2.Net is that essentials need to be stripted, and if you can't script properly, you're lost.
Example:
L2Walker: bot is on his bot routine, he tries to kill monster, monster can't be seen, it ignores it and moves along to kill another monster.
L2.Net: bot is on his bot routine, he tries to kill monster, monster can't be seen, bot is stuck. You need to make a script for anti stuck, but if you're using an xp script, then you need to merge that anti stuck and xp script together. If you can't do this (you're unable to write scripts), you're screwed.
What is quite sad is that L2.net is such a small project, I mean not everyone knows about it unlike l2walker, so there are few scripts. L2walker scripts are spread all over the internet, made by everyone.
But still I like that there are people that are actually improving and developing it.