Jane Iredale Handi Brush, with its compact size, is useful to apply all of Jane Iredale's powders but it is not a must have in my opinion, since many other good quality natural or synthetic brushes can do the same job as well.
When I used this brush for the first time, before washing it, it felt quite compact and firm, though soft and I ended up picking up too much product from the pan and depositing a thick layer on my skin because of its cut straight across shape. After I washed it, it splayed a little bit and became softer, thus applying powder more sparingly but also less precisely to small areas (under my eyes and around my nose).
To tell the truth I find that my Bobbi Brown bronzer brush, which is bigger and slightly domed, or even my Bobbi Brown Blush Brush, which is flatter, apply Jane Iredale's PurePressed Minerale Base more easily and evenly all over my face. To reach the small areas of my face I just use a smaller brush like Nars Large Dome Eye Brush (under my eyes, around my nose and on critical spots) and any blush brush for blush.