Well, to get scanlines from an Edge, you would need an HD Fury and a scanline generator. The HD Fury is $100, I think. The SLG-3000 is something like $70, although I would recomend the
T-SLG as it is cheaper and has more functionality. Scanlines, for me, are the biggest reason to get a scaler, so the Edge would be more expensive in the long run.
Aside from this, XRGB mini does a much better job at scaling the low resolutions that old gaming systems output. I do actually own both of these scalers and I would recommend the mini over the Edge.