I love Ian and would use it gladly. Evan just doesn't have the same classic lightness; plus, the only Evan I've known was mildly unpleasant. All the Ians in my life have been wonderful, with one brief exception.
Hard choice for me because I love both names. However, I prefer the name Evander to Evan. So, I’d go for Ian (since it isn’t as popular). If I could make it to my preference: EvanderIan.