Kyle Katarn vs ESB Darth Vader

MasterCilghal wrote:

 BreakofDawn wrote:How powerful is Luke at this point as compared to ROTJ? Has he actually grown in power by any notable margin?

Yeah he has, based on several quotes: 

Sidious: You’ve grown very strong in the Force since last we met...

Source: Dark Empire #2

The Jedi Master looked at me and I felt electricity run through his blue-eyed gaze.
When we had met before I had felt power in him, but now, after his experiences with the Emperor Reborn, his power had been redoubled.Physically he looked a bit haggard and worn, with the flesh around his eyes having tightened and wrinkles appearing at their corners. I knew we were the same age chronologically, but in experience he far surpassed me.

Source: I, Jedi

Take into account that JO takes places in 12 aby while DE in 12 aby. There’s even a statement wherein Luke says he’s grown even stronger after Exar Kun was defeated but I don’t have it with me atm.