Does anyone use checkinsooner.com?

[MISSYLEXI]

I saw this link on another post and was wondering if anyone uses it and how well it works? Do you have to use it both ways or can you just use it for your return flight?
I have SW and I do not know if I should try it or not. I would like to get boarding pass "A" because there is 7 of us flying together.
Thanks in advance for your help.