Sylk is a water-based, all-natural, paraben-free, personal lube.  It is pH “balanced” to be similar in acidity to vaginal pH levels, is safe with condoms and safe to ingest.

Most of the reviews I found are overwhelmingly positive, like this:
“…the most natural feeling synthetic [by which he means externally-applied, not chemical-based] moisturizer, bar none…”

A few people said it gets sticky; many said it did not, so I suspect the difference reflects whether or not users were familiar with natural products.  (None of the natural lubricants seem to stay wet quite as long as silicone-based products – a trade I will gladly make!)