1) Haven't tried it yet, hear its fun or bad depending on if you have a pocket healer
2) I run solo with a companion whilst on vent with my friends and still having a blast murdering things
3) I'm attacking things 2 and 3 levels higher than me, sometimes in packs, sometimes 2 silvers, sometimes even a gold is thrown in. It gets hairy but for the most part I win
4) This..a million times this
5) profit?
All I can really tell you is get some orange gear, mod it, get your companion some orange gear, mod it, and did I mention Mod your gear? Keep your stuff updated with mods. Use your commendations from the planets to keep your and your companions loots on the leveling curve.
This is a fun class, albeit it needs some polish, but its a fun class that you have to pay attention to fight well and not hit the "I WIN" button. Story is very engaging thus far (I'm 42 on Belsavis), the mechanics are great, and murdering everything as dark side is sooooooooo fulfilling