I've been on Plaquenil since around 2005. Initially I had some nausea but that got better within a few weeks of taking it and when I started taking it with my meals. I also had ear ringing and stopped it for awhile - we were never sure if it was due to the Plaquenil because it didn't get better when I stopped it, but it did eventually go away after about 6 months.
Unfortunately all my symptoms flared when I went off of it so I decided to try it again after about 10 months. No problem with ear ringing or nausea this time around and I have been on it for about 4 years now this time around.
It has really helped with my joint pain, fatigue, skin rashes, and my eyes aren't as dry and my ANA and SSA have decreased, my sed rate is now normal. I didn't notice as much improvement with my dry mouth so went on Evoxac and that has helped tremendously for that.
I haven't had an issue with parotid swelling, brain fog, or gastroparesis so I can't comment specifically about these, but my understanding is that Plaquenil slows the progression of the disease so decreases the damage the autoantibody complexes and inflamation do to various organs/systems.
Good luck with your decision and let us know what you decide and how you are doing.
If you are med sensitive you might want to start with 200 mg initially and if you do OK with that, then increase to 400 mg which is they usual dose. And be sure to take it with food!