When a person chooses a permanent synagogue, he must take into consideration several factors. If the choice is between a beit midrash (study hall) and a synagogue, it is better that he establish his place in a beit midrash, for it is holier, and prayers recited there are more accepted (Shulchan Aruch 90:18). Even when there are fewer people praying in the beit midrash than in the synagogue, the beit midrash is preferable (Mishnah Berurah 90:55). However, if he cannot assign a set seat for himself in the beit midrash, it is better that he designate a place in the synagogue.
When he has the option of praying in either of two synagogues, he should choose the one that offers more Torah classes, since it is considered more like a beit midrash. In addition, it is preferable to join the congregation that places greater emphasis on Torah study.
If there are two synagogues, one in which many people pray and the other in which few pray, a person should prefer the one with many, for “B’rov am hadrat Melech” (“In a multitude of people is a King’s glory.”) However, if it is difficult to hear the chazan clearly in the larger synagogue, it is better to choose a synagogue in which one can properly hear the chazan (Mishnah Berurah 90:28). Therefore, as a general rule, it is best that synagogues be as large as possible, so as to augment the respect of Heaven. Nevertheless, there is a limit, since when there are more than a few hundred congregants it is difficult to hear the chazan clearly.
If in one synagogue people regularly chatter during prayer and in another they don’t, a person should opt for the synagogue that shows more respect for prayer, for he will be able to concentrate better there (Sefer Chassidim 770).
The most important element of prayer is one’s kavanah. Therefore, above all other rules established by the Chachamim, the place in which one can personally concentrate better is the appropriate place to choose (see Radvaz, part 3, 472).
Similarly, it is proper for a person to pick a synagogue in which the congregation prays in his family’s nusach. However, if he knows that in a different synagogue he will have more kavanah, he should choose the synagogue in which he can have proper kavanah (see further in this book 6:3).
A person is rewarded for every step he takes on his way to synagogue. Therefore, even if the preferred synagogue is farther away from his house, he should not be concerned with the trouble that it takes to walk there, because he is rewarded greatly for each step.
. We learn about the reward gained for steps taken to come to pray from the story of a widow who walked to Rabbi Yochanan’s distant beit midrash (Sotah 22a). It is implied from many Acharonim, among them the Mishnah Berurah 90:37, that if a person has to choose between two synagogues, all things being equal, there is an enhancement of the mitzvah in opting for the one farther away in order to merit the reward for steps taken. However, some Acharonim write that only if the farther synagogue is preferable anyway – whether it is because it has more people, or because it is a beit midrash, or because he can concentrate better there – he gains the reward for steps taken to walk there. However, when there is no advantage in going to the farther one, he does not receive reward for his steps taken to walk there (Petach Einayim, Sotah 22a; Divrei Malkiel 5:19; Maharshag 1:27).