I haven't tried the Nature's Flavours, personally, but the ingredient information (including hidden carb items like glycerine, etc.) should be listed at their website. Try www.naturesflavors.com and let us know what you come up with...

Also, I believe they are available online only (US-based) but do come in plastic bottles, which weigh a bit less, even if the contents still weigh a lot. Their website MIGHT have stores listed, some do. If you live in the US, this could be of use to you. If you live in Canada, check the LowCarb Co-op forum for availability of DaVinci...

PS: The ATKINS brand of syrups is made under contract by DaVinci Gourmet, to their same high quality standards.