I lucked out when I got her. I was trying to get Shimakaze, myself (still haven't managed to get one).
I-168 is a commitment though, I will say that much. While she's great for taking hits (I have her maxed out on everything so she can actually take one, when they actually connect) and takes no time or resources to repair, you may as well be sacrificing a fleet slot, too, since she certainly won't help much with taking other ships down (though now that I have maxed her torpedoes out and given her my Isuzu Kai's torpedoes, she can actually hit sometimes). She doesn't seem to upgrade until lv50 though >_o
Oh, and while she's fantastic, regardless, her voice gets really irritating after a while. Definitely suggest not making her your flagship for your main fleet (but a flagship regardless)