Your bio says you have 6" of lift to run 33's.
I have a 3.5" spring lift, 1" body lift, 5/8" shackle lift and run 37's (I have tube fenders and a TJ cut rear well opening). The key to having a good working spring under system is to make sure you have the right springs, a hanger flip, and the right shocks.
Not all spring under systems ride like crap. Spring over requires a fair amount of engineering and still isn't for everyone. An SOA system will usually allow more front end hop while climbing than a SUA system. A few guys in my club that had had SOA for years went back to SUA. On an SOA system you have to have some sort of anti-wrap bar to prevent your springs from bending. There are many kits on the market and it's not a complicated installation. But overall, there's not really anything gained by a SOA compared to a decent SUA system.