G'day mate!
No, the Revell mould is thankfully not the Heller one - it's their own from around '98 or so.
Quality-wise It is as detailed as the Hasegawa one, arguably a little better (cockpit tubs are seperate and detailed underneath, for example, but wheel wells need to be cut out to see them)
The two things hasegawa did better are the gun troughs, and the way the nose fits together. Revell made the lower nose seperate, which needs alot of filling and sanding to correct.
They got the flare chutes correct though (Hasegawa didn't), and the panel lines aren't as deep. See the 'what's on the workbench' thread or my GB 10 'Mistel' thread for pics!