Hey Norman I have to say that the e:xl 16's are very good speakers. I run four of theses and a e:xl center in my setup. They sound great at reference levels and are sensitive speakers so they don't require as much power. I have everything crossed over at 80hz to my SVS 20-39 and I couldn't be happier. I have listened to the JBL's but not in my home so I can't give a honest comparison of the two. I would suggest a demo of both and then you can let your ears decide.
Later Haywood