It is a Miswah to be one of the 'Asarah Rishonim (the first ten men in a Minyan) for Tefillah (for any prayer), Shahrith, Minha, or Arbith. The earlier you come, the more reward you have, meaning the first person, has more reward then the other nine who come after him. It's all a question of levels.
Rabbenu the Arizal says in the Sha'ar Hakkawanoth, that there are those who would try to be clever and go to a Synagogue where they knew they could be one of the first ten, but had no intention of praying there. They would wait until there was more than a Minyan, then would leave and then go to another Synagogue where they preferred praying.
He says no, you not only have to be one of the first ten, but you have to pray in that place also.
(See Ben Ish Hai, Shana Aleph, Parashath Miqqes, Oth Aleph)
