One thing I forgot to mention. I love Sampo swivels. I've used them for as long as I've been keeping and flying birds. However, the main reason I went with a figure 8 style swivel the last couple of years is because I like keeping my birds tied on perches, on sand. With a simple figure 8 style swivel, there is no way for sand to get inside and potentially, even temporarily, cause the swivel to bind and stop turning. This was very important to me and is the reason I will continue to use a traditional, figure 8 style swivel.
All my best.