It is a truth universally acknowledged, that one cannot have too many (or even enough) blending brushes. You just can't. I often use more than one blending brush per makeup application, as I like them to buff in concealer, apply a tiny amount of setting powder to a small area, and obviously, to blend eye makeup. Back in 2010 when Lisa Eldridge posted her favorite makeup brush video I already had several of her recommended tools, but haven't heard about this line by UK-based makeup artist Daniel Sandler. A quick e-commerce transaction later (and about a week before the package arrived here) and I was the owner of Daniel Sandler's blending brush.
It's been quite a while since then, and as you can see the hair has splayed quite a bit from use and washing, but Lisa was right, and this is a good work horse. Daniel Sandler Blending Brush is made of natural hair (though they don't saw what type of hair. Could be either goat or pony) and works better with powder products than with creams (both Paula Dorf crease and MAC 217 can and should be used with either). It has to do with the shape- the Danile Sandler flares considerably. It's also more suitable for larger creases and lids such as mine. I find the brush reasonably soft (hey, it's not squirrel) and very efficient for blending and creating seamless color transitions and gradients.
Daniel Sandler Blending Brush has longer hair than MAC 217 and is not as dense, hence a floppier/fluffier feel (better for cleanup, not as efficient when buffing). It's far less directional or precise than Paula Dorf Sheer Crease brush which to me is the gold standard in this category. Daniel Sandler has created a decent brush that does what it promises, but in my opinion it's not a must-have if you already own several excellent blending brushes, and there's definitely no need to to go on a quest to have it if it's not easy for you to find and buy or if the exchange rate is not on your side.
Daniel Sandler Blending Brush (£16.25) is available from danielsandler.com.