These are the only two reels ive owned so i can give you a pretty good comparison. The I's are a bit smaller and lighter feeling in hand than the E's. The I's are maybe a touch smoother casting reel bone stock. The I's will not stay dialed in from cast to cast and you constantly have to tinker with the brakes and cast control. This was really annoying to me, once you get the E's set theyre good to go. The E's feel more solid in my hands and ive put a ton of miles on mine without a single issue. I think the E's are proving to another bulletproof reel from Shimano much like the old "greenies". The I's havent been around long enough to tell. They both have their pros and cons and id suggest getting one of each and using them to see what fits you best