mechanical device trust.

[MuniciPAL]

i recently purchased a petzl grillion, and while climbing with it i realized i have a trust issue with mechanical devices while im up in a tree. i cant seem to bear all my weight on it while moving my rope. even though i know how the device works i feel somewhat uneasy. is their anyone else that would prefer a prussic loop opposed to a camming device?
have people seen these devices fail and under what circumstances?

 

[MuniciPAL]

ic treeco, how do you back up your ascenders? prussic cord tied above them?
these mechanical devices are all new to me and im uncertain about the operating procedure.

 

[moray]

Like TreeCo I use two CMI ascenders, each backing up the other.

But I have to ask this: since a prusik is a mechanical "device", as is a carabiner as is your saddle, etc., is there some reason you are comfortable that a single prusik will not let you down but you are worried about your Grillion?

 

[MuniciPAL]

im not entirely sure. i think im just more comfortable with rope on rope.
i would like to see two trucks pull on a lanyard to see what it does. that would help seeing it under extreme circumstances.