All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
The person led in prayer should not recite the Al-Faatihah (the opening Chapter of the Quran) verse by verse at the same time the Imaam is reciting as this is being distracted to listen to the recitation of the Imaam. Shaykh Ibn ‘Uthaymeen was asked: “When should the person led in prayer recite Al-Faatihah in the prayer, is it when the Imaam is reciting Al-Faatihah or is it when he recites a Surah (Chapter) after Al-Faatihah?” He answered: “It is better for the person led in prayer to recite Al-Faatihah after the Imaam has finished reciting it, this is so that he can listen to the obligatory recitation which is a pillar of the prayer, because if he recites Al-Faatihah while the Imaam is reciting it, he would not have listened to the pillar (the recitation of Al-Faatihah) and he would instead listen [in this case] to what comes after Al-Faatihah which is an optional act [Sunnah]. Therefore, it is better for him to listen to the recitation of Al-Faatihah, because listening to the recitation that is a pillar of the prayer is more important than listening to the Sunnah. On the other hand, if the Imaam says ‘wa la adh-dhaaleen’ and you are not listening to him, you would not say ‘Aameen’ (i.e. you will be engaged in reciting the last verse of Al-Faatihah instead of saying Aameen at the same time the Imaam says it), in which case, you are not following the congregation, and it is better to say ‘Aameen’ directly after the Imaam says ‘wa la adh-dhaaleen’.”
Also, Shaykh Ibn ‘Uthaymeen was asked: “Is it permissible to coincide with the Imaam during the recitation of Al-Faatihah, meaning when the Imaam starts to recite Al-Faatihah, I start to recite at the same time he does?” He answered: “It is better not to recite at the same time the Imaam is reciting Al-Faatihah, rather you should recite only when he would have finished reciting Al-Faatihah as in general he [the Imaam] would be silent for a while and the person led in prayer may be able to recite half of Al-Faatihah before the Imaam starts reciting a chapter after it. Secondly, if the person led in prayer recites while the Imaam is reciting a Chapter after Al-Faatihah, then he would have engaged in a Waajib (an obligation) instead of a Mustahab (a desirable act), but if he recites while the Imaam is reciting Al-Faatihah, then in this case he would have engaged in something that is not Waajib leaving what is Waajib. Therefore, we would say that it is better for the person led in prayer not to recite with the Imaam while the latter is reciting Chapter Al-Faatihah; rather, he should wait until he finishes.”
Allaah Knows best.