Modern historians have a much more positive view of Islam's contribution to science, the arts, and civilisation. Some historians would consider that Middle Ages Europe owed more to Islam than any other contempory source. The sheer breath and depth of knowledge and skills is beyond anything that I'm able to concisely portray on RF.
Islamic Golden Age - Wikipedia
Islam would be much more appropriately compared to Christianity and Judaism, than the Visigoths or Vikings. All 3 are Abrahamic Faiths, with a belief in monotheism, a Manifestation of God or Holy Man who has brough forth a revelation from that One God, and sacred text that with some degree of authenticity represent Their Teachings. These sacred texts have been the inspiration intellectually as well as spiritually that have stimulated the arts and sciences. In each instance there has been a flowering of civilisation.
Is it fair for a Christian to compare Muslims to barbarians because they have have conquered weakened lands when Christian history is full of such wars and conquests? How does Christian civilisation rate in regards to human slavery? Do the Teachings of Jesus or the Apostles explicitly forbid slavery? In regards to rediscovering the antiquities the Muslims readily recognised the treasure they had and made use of it. How about Christian institutions who clearly struggled for centuries with science, especially when it challenged orthodox belief. How tolerant were the Christians to other cultures or even other Christians, for example during the crusades?
I'm admittedly just a student of history but it appears that Islam had a golden age when Western Europe had the relative darkness of the middle ages.