I've always found SPD's feel less secure and solid than atacs, but it's not a big problem. I suspect that's just how they are and adjusting the tension is unlikely to make a difference. As Time quality control went downhill I've been happy to go back to SPD's. I have 520s on my fixed beater and their great. The Look X Track Race pedals I have on my other bike probably feel slightly better all round but the difference isn't massive.
I've always found SPD's feel less secure and solid than atacs, but it's not a big problem. I suspect that's just how they are and adjusting the tension is unlikely to make a difference. As Time quality control went downhill I've been happy to go back to SPD's. I have 520s on my fixed beater and their great. The Look X Track Race pedals I have on my other bike probably feel slightly better all round but the difference isn't massive.