Rabbi Yishaya ben Eliyahu di Trani, Italian Talmudic commentator (c. 1300)
A man should rather live in Eretz Yisroel, even in a city of mostly gentiles, than outside the Land, even in a city of mostly Jews, for whoever lives in Eretz Yisroel is similar to one who has a G-d, and whoever lives outside the Land is similar to one who has no G-d, as Scripture says, “For they expelled me today from basking in the property of G-d, saying, go worship other gods”(Shmuel 26:19). Nevertheless, Israel must not all go up together with a strong hand, in an act similar to the ingathering of the exiles, for they are not permitted to hasten the end, until the Creator hastens our redemption, as Scripture says (Song of Songs 2:7), “Do not arouse or awake the love before it is desired.”
(Piskei Riaz, Kesubos 13:8)

Rabbi Yitzchak ben Sheishes, Spanish legal authority, known as the Rivash (1326-1408)
We have established that for a mitzvah one is permitted to depart even on a Friday, and there is no doubt that traveling to Eretz Yisroel is a mitzvah. Our Sages have said, “Whoever lives outside the Holy Land is like one who has no G-d” (Kesubos 110b). And they said further, “Whoever walks four cubits in Eretz Yisroel is guaranteed a share in the World to Come” (Kesubos 111a). Although the prophet said to the exiled Jews, “Build houses and live in them” (Jeremiah 29:5), that was only because exile was decreed upon them, and the One who exiled them did not permit them to return, until they returned with the permission of Cyrus. And now as well, one of the Three Oaths G-d made the Jewish people swear is not to go up as a wall.
(Shailos Uteshuvos Rivash, siman 101)

Rabbi Shlomo ben Shimon Duran, known as the RasBash, leading rabbi of the Algerian community (1400-1467)
During exile, living in the Holy Land is not a general commandment for all Jews, but on the contrary it is forbidden, as the Talmud says in the last chapter of Kesubos, that this is one of the oaths that G-d made the Jews swear: that they not hurry the end and not go up en masse. Go and see what happened to the children of Ephraim when they hurried the end!
(Responsa of the Rashbash, Chapter 2)

Rabbi Samson Raphael Hirsch, Rabbi of Frankfurt, Germany (1808-1888)
He (Rabbi Tzvi Hirsch Kalisher, who supported peaceful Jewish colonies in Palestine) has written to me more than three or four times and sent me his writings and books in order to convince me to take a leading role in his movement to settle the land of Israel, until he finally came to me and accused me of delaying the redemption. I have requested that he leave me alone on this matter, for that which they consider a great good deed is to me no small sin.
(Shemesh Marpei, p. 216)

Rabbi Yosef Rosen, the Rogachover Gaon (1858-1936)
Regarding what you asked about settling the Holy Land, this is only for individuals, and we must not do it as a group, as it states at the end of tractate Kesubos, that we must not go up as a wall. See Yuma 9b [where it is clear that group immigration, even when peaceful, is considered ‘as a wall’]. The Rambam also holds that only settling Eretz Yisroel is a mitzvah, not buying land there. For in this matter there is a contradiction between Gittin 8b [where it states that there is a mitzvah to buy fields in Eretz Yisroel] and Bava Kama 80b [where only houses are mentioned], and the Rambam (Hilchos Shabbos 6:11) rules in accordance with Bava Kama.
(Letter to Rabbi Yitzchok Sternhell of Tzanz, editor of the monthly Torah journal “Hakochav”, printed in Tikun Olam)