Switching to dutasteride, currently on finasteride 1mg daily for 3yrs with 0 side effects, will I respond the same?

Great question!Dutasteride theoretically has more potency for hair preservation than Finasteride but a higher side effect profile as well.  The use of dutasteride for hair loss is an off-label use according to the FDA.  Typically regrowth of both agents occurs in areas where the hair is miniaturized and not where slick baldness occurs.  Consider the use of regenerative techniques such as PRP and others and the use of nutraceuticals such as Nutrafol which have a much better side effect profile.Best, Dr. Anil Shah

It's really hard to say. Your DHT will likely drop a bit more. One can not predict how your body will respond. The odds are in your favour of course, but it is not a guarantee. The reality is that many men do great on dutasteride. 

There is no reason to switch from finasteride to dutasteride in your situation. Remember dutasteride is not FDA cleared and may cause sterility.