I have no input on the E3 MT, but E3's in general are not my favorite tire anyways. They last a while but are noisy and on smooth roads, while going around bends in the road where you have to lean a little, you can feel the ribs. Feels like a bearing or something is going bad....... Cought my breath a few times.
I did some reading and people who have tried the new Avon Cobra's liked them, I haven't read anything bad about them. When I got my bike, I had them installed and love them. THey offer a ride like the Shinko 230's did, smooth and soft as could be. The grip so far seems good although I haven't gotten to spirited on them yet. Have put on about 1500 miles on them so far and like them. Others have reported 12K miles and the tires still look good, so with that, I suspect 15K to 19K average range for at the rear tire, perhaps more for the front. I would think they are comparable to the E3's, wear, grip and price, but I can say the ride is fantastic!
Stick with the EII's on the 1200, or if a 1500 go with the battleaxe rear tire turned backwards on the front (I did this on my 1200 also) and the Austone on the rear. (will not fit the 1200 stock rear rim)