I've been using this product for about 2 weeks and have noticed a slight whitening effect over this period. I cannot comment on the recalcifying, as this is not something I have noticed. The product is easily taken twice a day - swish it around inside your mouth after morning and nighttime brushing - although the absence of a measure within the cap means you have to guess or measure it out with a spoon - I've just guessed the centre of the cap as 15ml and it seems to be working so far!
I haven't noticed any unpleasant taste in respect of food and drink, though the taste of the mouthwash itself is slightly saccharine-like. Will keep working with this to see how things progress.