So based on your info, overall SF would be a better purchase unless you wanted a higher wattage?The K7 V2 and the Smat Farm lights are both 95W lights.... the Smat Farm lights have a better lens though, so I would opt for the Smat Farm light over a V2.
The V3's are 140W, have warm white drivers that the V2 doesn't, and also has slightly different spectrum due to different drivers between V2 and V3.
V2 had 410nm and 420nm drivers.
V3 has 405, 415, and 430nm drivers.
Smat Farm has 410, 420, 430, 450, and 457nm drivers, and warm white.