They last for a gizzilion miles, but they make the bike handle like a truck !. just my two cents.. the Pirelli Night Dragons were top performance worst life, followed by the ME 880, but nothing handled worse than the dunlops.
I'm running E3's front and back on my 08 Softail. Have put about 1000 miles on them and they handle road grooves etc better than the stock Dunlop tire for these bikes.
The rear tire is actually a little bit narrower than a 150 size which is the stock rear tire on a Heritage. The sidewalls are much stiffer that accounts for the increased load carrying capacity.