I would be embarrassed to use a merc with my sks though. Ranger should be okay. I'm not fighting anything hard though
Soloing with or without mercs is pretty much my play style these days, and a ranger will be absolutely fine to solo on from what I've seen.
TBH, play a class that resonates with who you see yourself as a player. This is a toon you will be living with for some time, so make your gaming choices wisely, young Jedi. If you base it on who's easier with a merc, you'll be chasing classes. Start with what's important--it ain't the merc, Grasshopper.
I use a merc with my SK all the time when I'm harvesting. Him and my squire beat up mobs that try to bug me while I'm out collecting fruits and vegetables.