Best tires for your bike is based on many factors, but it boils down to only two...use and personal choice. OEM Dunlops are preferred by many because frankly they have been married to HD for the past 20 years or so...and plenty of R&D has gone in to finding the right combo of mileage and performance for the HD high profile, heavy weight V-Twins.
Some have found that though they have great mileage, they are not as "sticky" as they would like or just brand dissatisfaction or special needs warrant a change. Popular alternatives major brands include Avon, Metzler, Michelin and others but the actual line that separates them is very blurred and fairly narrow, perhaps the last 25% of a tires' overall appeal...performance, mileage, style or features...the greatest discision maker being the right wrist to brain connection, specific application and price.
Happy hunting...and look in the Self Help and Search threads for specific info on your brand and get some background info on your tire selection.