What struck me most about the F80 was the quality of it and the attention to detail. From the solid handle, soft bristles and the embossed logo this is definitely a brush that is going to withstand the test of time in my collection. It even came with a nifty little plastic protector which will be ideal for keeping it dust free when not in use.
The Sigma F80 is a lot denser than the RT buffing brush but still has a soft finish which meant applying liquid foundation with it was a dream, even getting into all the nooks and crannys such as the creases of the nose and eye area and left a pretty flawless finish. Having never tried a Sigma brush before I can definitely see what all the hype is about. The F80 retails for $16 which equates to just over £10 as I understand so for what you get its an absolute steal considering what you could pay for alternative high end makeup brushes such as MAC.
* PR Sample. Some links are affiliate links.
Have you tried Sigma brushes and what do you think?