From what I recall, even Mara Jade was canonically ahead of Jerec overall, so I doubt the latter is comparable to Vader.
His other feats are stunning Rahn, which I don't think is as powerful as Fay, and he disintegrated a ramp that held a ship, which I doubt is beyond Asajj's level when she's canonically better than beings that can choke AotC Annie or K'kruhk, both of whom manipulate ships.