I run both LE and Kodi / Windows, my thoughts:
1. Picture quality is equivalent (Windows required tweaking with the almost unusable and incomprehensible Graphics Command Center - thanks Intel).
2. On my NUC7 & 8, both are smooth and fluid with heavy skins, and play all h264 content perfectly.
3. Scraping is actually faster under Windows (both are using the same NAS with SMB v2).
4. I haven't noticed Windows Kodi running any warmer than LE on the same hardware.
5. One Windows benefit for me:
- My audio is only 2 channel stereo, Kodi > HDMI > Samsung TV > optical TOSLINK > SMSL Q5 Pro 2 channel DAC/amp, with no L/R balance adjustment. In Windows I can adjust L/R balance in Windows audio, but LE lacks that feature. I've tried using alsamixer but with no success.
I switch back and forth between boxes as my mood takes me, but both Windows Kodi and LE work great for me.