I use one and love it, especially for APA and AIPA styles. Cuts way down on hop matter in the fermenter. In theory it can slightly reduce hop utilization, but in practice I don't add extra hops to compensate, and my IPAs are plenty bitter and hoppy. Let me say though that I use a 5 gallon paint strainer bag clipped to the side of my kettle as my spider, so there is plenty of room for the hops to circulate freely.