It depends on the type of applique. I like small thin ones for cutting out fused applique like the second pair shown here (green 4 inch).

For machine EMB applique I like these. They get into tight corners. I hold the fabric almost straight up and trim close.
http://www.havelssewing.com/snip-eze...ors-33010.html

I don't like the duck bill ones for machine EMB as I don't get close enough.