To choose between different techniques, the size range is usually the prime factor. The chosen technique should identify not just the median size, but the full range of sizes in the distribution. In cases where more than one instrument covers the desired size range, consider other possible samples and possible future developments. For example, a new product with a larger particle size may be introduced in the future. This may suggest that the analyzer with the higher upper size limit is a better choice than an analyzer with a smaller lower size limit. Figure 1 below shows the size ranges of some techniques.
A note of caution: The stated size range for an analyzer does not apply for all samples and all cases. Choosing an analyzer such that the particle size of the sample is in the middle of the instrument size range is almost always wise. In general the data is better and you are better able to work with variations in particle size about your expected value.