Ayed - it depends what you mean by 'powerful'. Both are established and have a similar reputation/usage. They use slightly different metrics to gather their information and different discipline lists to report - so their lists of journals by disciplines can vary a little. I use both or either as there is not much difference. My institution stipulates journal quality measured by Q-ranking - so Scimago is the better option if I want to readily see Q-ranking as well as Impact Factor.
Many thanks to Dean, Segun, and Mohannad for their contributions.
By the way, the publication in the journals measured by Q-ranking (SJR) is a little bit less complicated than those measured by Clarivate (impact factor-JCR). Is that true?