Machine Matzah: There is a big machlokes haposkim about whether one is allowed to eat machine matzos on Pesach. Those who forbid, hold it may even be chometz gamur, and those who allow it hold that they are more mehudar than hand matzos. Nowadyas, many of the original concerns no longer apply and there is no concern of chometz with machine matzos. Some have raised concern with today’s machine matzos, and according to them the machines matzos of today are chometz gamur. However, gedolei hador have already said that machine matzos of today are kosher lemehadrin.
Lishmah: Another point of dispute is if machine matzos are considered lishmah, and if they can be used for Seder night.
All Seven Days: According to the Vilna Gaon that there is a mitzvah kiyumis for every kezayis of matzah that one eats on Pesach, some say one can use matzah that isn’t lishmah, and some say one only gains the opinion of the Gaon if he uses matzos that are made lishmah. According to the stringent opinion, one should be machmir to use hand matzos the entire Pesach.
Minhagim: There are four different minhagim. Chassidim generally use only hand matzos. Minhag Yerushalayim and kehillos of German and Hungarian ascent use only machine. Most of the world - for the kezaysim on Seder night use hand and for the rest of Pesach use machine. A fourth minhag is – meikar hadin machine is good even for Seder night, and as a chumrah one should try and use hand matzos.
