Come along for a jaunt on Emma, my 2007 RE Bullet. Experience the sound of happy valves as we tour central Pennsylvania farmland. I chatter a bit about why I like her and some things you should consider before getting your own Bullet.
That is what a real motorcycle is supposed to feel and sound like. Lugging any engine will destroy it quickly. But the Enfield does not like to be revved too high either. It is a long stroke single, and that big piston wants to fly right off the end of the rod every time it passes TDC. I ride my 2013 UCE Enfield (converted to an Amal carburetor) at about 55 mph indicated in top gear on fairly flat roads. That seems to be it's sweet spot. It just rumbles along. Going much faster will overstress the engine. And yes you do need to downshift to climb hills. One thing an Enfield does not have is power, but that is not why you ride one. You ride one for the vintage British bike riding experience, which is FAR superior to any Japanese bike.