Luis
I hope you can do a little more research. Or at least look further. Both loco's sell for at least half that here in the US or other web sites (or where you quoting Euro's?).
As far as quality, these are both older LL's and do not have the split frame chassis. The E is heavy and does pull decently but how many passenger cars are you going to pull? The SD has fly wheels (One of the first LL's to have them) but all the ones I've seen run don't seem to be effective. Both engines are noisy and high speed runners. They will use a very small portion of the throttle range.
I would recommend either the LL GP20's or their SW1200 over SD7/9 or E7. If you are looking for a passenger engine the LL PA is better then the E7. The real way to go if you can afford them is Kato and Atlas. I have large fleets of both that I'm very happy with. The few LL's I have are good and they do have great paint jobs, but don't run as smooth as the others and are quite abit noisier.
Just my opinions.
Jim