I use a shadow.. but I really don't use all of it's weapons. I'm not sure how they really fair now that there is a new balance update. Take note: My information is flawed.
The only weapons I use that come with the Shadow are the nexar bombs and the cloaking device. My main weapon is the scatter shell (golden heart). Combined with using infested missiles. I also use Hunter-killers for shield debuff. I only use the nexar bombs for specific enemies (cleaner, multiple small enemies, revealing stealth bombers, advectorian, and maybe some other things).
For defense.. I am using a shield regen build.
Those are pretty much the basics. Again, I don't use the blaster or the projector because before the balance update I found those weapons useless. They might be good now.. but I haven't even tried to explore those avenues.
About the low power usage thing, you could have in your artifacts, a power generator, which gives you more power regen. That would help a bit.