It seems that an astral suit that's like armor is identical to that armor in all ways—armor check penalty, speed reduction, weight, and more
On Astral Suits on Astral Suit Types on Astral Armor, in part, says
And Astral Juggernaut, in part, says
The phrase all mechanical purposes strongly implies to this reader that these astral suits are just like the armors they emulate, including the emulated armor's weight, armor check penalty, speed reduction, and arcane spell failure chance.
The only additional indicator that I can find that backs up this reading is the 1-point Customization Flexible Suit that says
The aegis’s armor check penalty is reduced by 1 (to a minimum of 0). The aegis may also sleep in his astral suit without becoming fatigued, if he was not already able to do so (such as if in astral skin form).
On Armor Check Penalty, in part, says
A character who sleeps in medium or heavy armor is automatically fatigued the next day.
This customization again strong implies that the astral armor and astral juggernaut effects are just like the armors they emulate unless exceptions are made, even down to details that some folks might otherwise overlook.