Thanks for all the comments, I really appreciate them. I would like to pose my question more precisely: I believe that the required grades ( and all other necessities) are achievable (perhaps with the exception of Oxbridge) and I have not yet sat the BMAT or the UKCAT, so I will have to consider that on a later stage.
I know that the degree I'd get would be the same from any medschool; however, I believe there is a difference how they teach, how the medschools are organized. The medschools will have to display their very own profile to attract students like us.
To explain where I stand at the moment, here are my thoughts (wich most embarrassingly show that I hardly know anything at all): there are the two afore mentioned universities where you need to be truly excellent AND lucky to get in. Then there are the medschools in London; as a Non-UK-resident Imperial and UCL are better known to me. And then there is .... "the other universities". Admittedly, I have not been to any Open Days yet, but to me it's hard to see the difference between e.g. Aberdeen, Southampton and Edinburgh. That's why the rankings and some factors such as 'student satisfaction' come into play.
In other words: if you got accepted into more than one medschool, how did you decide (any factor which is related to medschool)? Was there a tipping point?