At university I had a teacher who taught specifically pronunciation - in his view good Russian pronunciation was very hard for French and Germans, not too difficult for English or Spanish, hardest of all for Poles, and easiest of all for Italians.

Italian I can sort of see - the quality of the vowels seems similar. A German colleague had terrible problems, though his Russian in other ways were good - in Russia you could hear the German students coming a mile off! Polish I suppose the similarity of words might inhibit correct pronunciation.