The B-58 was a beautiful aircraft, I chose it as one of the most beautiful aircraft. It had a reputation of being a difficult aircraft to fly. I suspect that when everything is working it would be no harder than an F-102 or F-106 to fly. However, initially it did have a fatal flaw. When flying supersonic if an engine failed the instantaneous yaw would cause the plane to disintegrate. This was fixed by automatically shutting down the engine on the other side when the failure was detected. Quite a few years ago I worked with a man who had flown both the B-36 and the B-58, I don't remember him saying the B-58 was particularly hard to fly.
As far as range goes, it is often difficult to compare aircraft and the data often does not contain the conditions in which the data collected.
For instance, one source defines the B-47 weapons load but does not provide any data for that for the B-58. That said, USAF Museum states that the range, not radius, of the B-47 was 3935 miles and the B-58 was 4400 miles. No load factors were provided. Another source stated that B-47 with associated weapons load, 10k lbs, was 2315 mile, and the B-58 radius was 1740 miles but no load factor was given. All the miles are statute miles.
Combat performance for the B-58 would be for cruise speed, .91 Mach, about the speed of a modern airliner,, and then Mach 2 for weapon delivery. Supersonic cruise in this error required a significant amount of thrust that's only provided with afterburner which is a voracious consumer of fuel. If I remember correctly, in the T-38, if you used the afterburner all the time, which we did on what we called a burner flight, flight time was about 15 minutes. We would take off, climb to altitude, fly and arc supersonic to the inbound course and land.