Difference?

Usually none other than what kind of power turns the the propeller. And how much that costs.

When a specific airplane like a Nexstar begins life as a glowfuel model, the amount of power is usually part of the design. They develop the airplane as say a 40-size. And work out the details with that in mind. When it's then retrofitted, the motor, batteries, and ESC are selected that will fly that plane with power that matches what was available from the glowfuel version. Will there be a difference in performance? Only if the electric developer chooses a less powerful motor or a more powerful one.

Today's electric power trains wind up weighing significantly more than a glowfuel power train of equal power. So today, the electric version of any model will have a slight weight penalty. Most new modelers will not notice the difference in performance that comes from that weight.