By far the easiest hovering plane I have flown is the UCD60. However, it doesn't hold a steady Harrier like my Kangke Fun 50. A coroplast airplane like a QHOR or SPA3D make good 3D trainers because they hover and harrier well, and you aren't afraid to try new things down low with them. Another option is getting an 80"+ scale aerobat and learn 3D with that.