shRNA Plasmid propagation in Xl1 Blue - (Sep/07/2006 )

Hi folks,

does anybody know if Xl1 Blue is an appropriate host strain for propagating shRNA Plasmids?
does anybody know if Xl1 Blue is a phage resistent host strain ?

Gucci 13

generally i use DH5a for plasmid preps, of plasmids containing a shRNA sequence. But i've also used XL1blue for that purpose...