1) I'd be skeptical to distribute my raw DNA all around the web on free tools...
2) I think that most of those websites do horrible scientific shortcut between a complex biological system and diet/detox(whatever that means)/disease
3) I don't think any of the tools can be reliable at this point. There is a huge lack of causation/ significant statistical data linking any SNP data to diseases.
Besides if you have a mutation in Lactase gene and you can't digest milk but I don't think you need a DNA test to tell you this.