A large range of different safety razor blades from different manufacturers were tested under similar conditions over a period of time. The most popular and the lesser known blades along with several expensive blades were tested. Some blades were of good quality and could be used for more number of shaves while others had to be discarded too soon. The best safety razor blades chosen are often a matter of personal choice but the make and manufacture of a blade decides its suitability to the user. While some are of good quality they are too expensive and not economic. According to http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3559025/ the sharpest of blades even cause injuries that may need medical attention.
Feather stands out as the best and sharpest blade in most user reviews. It is suitable to those who are well experienced with shaving and have coarse beards. It is not very suitable for those with sensitive skin. Beginners would do well to look for less sharper blades to avoid injury and burns. The blades are platinum coated which keeps the surfaces non-stick to improve the quality of shave and also enhances the life of the blade. The pack also comes with an easy and safe disposal slot to put the used blades in; this makes disposal convenient. It is more expensive than other blades.
Astra Platinum is another shaving blade that is as popular and performs as well as Feather except for the fact that it is not as sharp as Feather. A single pack consists of 100 blades and the pack unlike Feather does not have an easy disposal slot. Astra blades too are coated with non-stick platinum to improve the quality of shave. It offers good value for money and is not as expensive as Feather.
Personna too is a popular brand among shaving blades. It is sharp and good enough for thin to medium beard thickness. It has a non-stick glide coat that enables the blade to deliver a good shave. It does not last as long as the above mentioned blades.
One may wonder why all the work behind determining the best double edged blade when hi-tech multi bladed razors are in vogue. But then the fact lies in the simplicity of the double edged blade and its quality. The multi bladed razors tend to clog easily especially when used on growth more than a day old and are difficult to clean. Other than this, the double edged blades are much more cost effective than the multi bladed razors. The double edged blades are more precise than multi bladed razors when maintaining detailed beards or sideburns. The precision and clean shave provided by double edged blades is superior to that of multi bladed razors.
The overall quality of shave mainly depends upon the blade quality but is also greatly affected by skin type, beard thickness, water quality and other shaving accessories such as brush and foam. A well lathered beard is easier and smoother to shave. Hardness of water will lead to less lather and also quickly degrade the quality of the blade. For an overall good user experience one might determine what works best for them with experimenting alone.