When I played as a Sith Marauder (using Carnage spec), I ran from no one... okay I ran from a couple of fights, but the best way I knew of to deal with them was to simply give a full-on attack with myself and Vette. Why? Because it took less time to kill the mob than it does to run away... like I'm talking literally a couple of seconds here as both Vette and I killinate the entire mob with such ease.
There's very little you can do to screw up unless you agro multiple mobs and even then you still have a chance if you kill them fast enough before they kill you. Plus it's quite a rush when it does happen anyway since the majority of the time when it happened to me... I survived. Vette didn't, but I did and I'd have to dismiss and call her back quite a few times lol.
The point is... everything falls before you in an instant, and that is good.
Also, ease of tanking depends on the class you choose. I haven't done tanking with the Guardian/Juggernaught or Shadow/Assassin, but most people tend to agree that Vanguard/Powertech tanks are the easiest to pick up... at least I found it particularly easy to pick up and not long ago I was totally new to MMOs and chose the Vanguard in tank spec as my main. Vanguards/Powertechs tend to have a lot of mobility which is probably why a lot of people find them easier to use, though compared to the other types of tanks, they're not considered the best, just the easiest to pick up.