I've actually put up a thread on how the first impressions for an Evil playthrough is important and would love to hear everyone's thoughts on that. For my part having done 6 characters evil, I would agree with most of what is being discussed here.
My most memorable moment at the moment in an Evil playthrough is actually my Halfling Hunter. I placed her where the elevator was in overlooking the Ritual after murdering the 2 tieflings around (left the squirrel but he didn't seem bothered that I offed 2 Tieflings in front of it). From my vantage point, I went into stealth and took a shot at the druids doing the ritual. I killed 2 before they went apeshit and started rushing down the Tieflings and killing them. I sat back and enjoyed the carnage. This was what I did immediately after coming in and did not agree to anything with Zevlor. In my "theatre of mind" the Halfling was just Chaotic Evil and wanted to push the druids to take action. Interestingly the Tieflings won, (somehow the druids Entangled their own team in a choke point and got picked off one by one) and they then decided to stay to defend themselves from the Goblins.
It did make this particular run enjoyable. This was only possible with the knowledge of the prior playthroughs though. My first evil playthrough bugged out at the Grove, Minthara just wouldn't talk to me even though the Grove was cleared.