All Praise is due to Allah and peace and blessings be upon His Messenger, his family, and Companions.
Juristic differences in the detailed issues may occur among the Four Juristic Schools due to certain causes, i.e. some jurists may classify a certain report as reliable; whereas others may regard it as weak, some may know of a Hadith while others may be unaware of it, etc. A Muslim should think well of them all. Each of them is a Mujtahid (a scholar qualified to exercise juristic effort to infer expert legal rulings) regarding the issues of jurisprudence as long as he seeks the truth. If he is correct, he shall have two rewards; a reward for his effort and another for being correct. If he is wrong, he shall have the reward of effort and his fault is forgiven. As for the practical adoption of those Four Imams, (Part No. 5; Page No. 25) whoever is able to follow the truth through evidence, should do so. If he is unable to do so, he should follow the trustworthy scholars as much as he can. This difference in juristic branches should not lead to abandonment of performing Salah behind one another, but they should perform Salah behind one another. The Companions (may Allah be pleased with them) differed on various issues, but they used to perform Salah behind one another as did the Followers and those who followed them in righteousness good.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.