In reply to LewisFisher:
I have had a Birdie for a year or so and really like it but there are several little quirks that I would say do not recommend it for group/beginner sessions.
The rope can flip around while lowering and I have found that the best 'deadhand' position to prevent this is either really close to the device wearing gloves or by creating a pulley by using a carabiner below . both require some experience and indeed the former method actually teaches bad practice for people using other belay devices. It can be very slick and unforgiving. My wife hates it!
I originally bought it to enable my wife to pay out slack without the snagging that sometimes occurs with a grigri, but she never uses it, although I do like to belay leaders with it.
It is to be fair a well made piece of kit and at least here in France slightly cheaper than a grigri but not for group use. (Indeed is a grigri?)