D90|10-24mm f3.5-4.5G|70-300mm VR f/4.5-5.6G|18-105mm VR f/3.5-5.6G|35mm f/1.8|SB700|MB-D80
To set the record straight, the Kenko PRO 1.4x is compatible with the Nikkor AFS 70-300mm VR and AF is possible but is rather but not painfully slow in good lighting.
It's more than good enough for distant landscapes (and stationary subjects) but would be heavily compromised otherwise.
IQ is subjective. Sometimes, you just need the reach.