No, Scotland's Ancient universities are comparable to England's, perhaps with the exception of Oxford and Cambridge which are considered to be something of a global elite.
The closest thing to a global league table, TES's World University Rankings had Edinburgh as the best Scottish University in 2012/13, and 32nd best in the world. In comparison with other UK universities, Oxford was tied 2nd in the world, Cambridge 7th, Imperial College London 8th and University College London 17th.