Which is better: praying the Fajr regular sunnah prayer at home and missing the opening takbir (takbirat al-ihram), or praying Fajr in the mosque and catching the opening takbir?

It is better to maintain performing the opening takbir (Allahu Akbar) in congregation due to the Prophet's (peace be upon him) saying: "Whoever prays to Allah for forty days in congregation, catching the first takbir, two immunities will be written for him: immunity from Hellfire and immunity from hypocrisy." As for the two rak'ahs of Fajr, they can be performed after sunrise, due to his (peace be upon him) saying: "Whoever did not pray the two rak'ahs of Fajr, let him pray them after the sun rises."