I use a blanket stitch on all my applique. You can vary the stitch width and length to suit you. I usually use smaller on smaller pieces and a bit larger on larger pieces, but always have the straight stitch right next to the applique, but on the background. If your thread color matches the applique you have to strain to see it. Only once did I use a satin stitch. It is much harder to get even curves but doable. This was on a bed sized quilt for a toddler and will be washed many times. I haven't quilted it yet, but will also stitch on the inside of the satin stitch to reinforce the pieces further. With satin stitch:
http://www.quiltingboard.com/picture...n-t267156.html With blanket stitch:
http://www.quiltingboard.com/picture...s-t268455.html If you look at the close-up pic, you can see my stitches in the lighter leaf, because I used a darker green thread. All the other appliques are blanket stitched too, but you can't see the stitches, especially from afar, because the thread matches. On folk art type appliques, I like to use black, which makes it look like it was done by hand. Your quilt, your choice. Good luck.