The GriGri Is a great device for in the gym or outdoors however if there is dirt in the device it may not function properly ( As I Found Out ) but otherwise works great.
if tension to the rope is not applied abruptly it may slip up to 3 metres.

if not for this i would without a doubt give the GriGri a 5 Star.

it is a great device. i certainly would recommend this to anyone.

From all the bad press this device gets, its really not all bad. for me it has performed flawlessly. But care must be taken when lowering and rappelling, the lever that opens up the camming device is a bit on the toutchy side. After several times of "playing " with this it deffanly is possible for get the grigri to lower you partner quite smoothly. other than being big and blukly its good for close one day single pitch stuff.

I put off buying one of these things for years. Now I don't know how I ever climbed without one. The main reason I bought it was for my wife to belay me on sport climbs where I would be hanging a lot. It has become my main belay device for sport cragging, top roping, and the gym. The other things I use it for:
* Solo TR (though other devices are better, IMO)
* Back-up to a two-jug system
* In certain situations as an ascender with one jug or friction knot
* Solo aid
* belaying leaders on big-walls (where you might fall asleep while belaying)
* belaying any leader where you can provide a dynamic catch by jumping

Things I don't use it for:
* Teaching beginners. I'll let some who has never used a grigri use mine if they are solid on a tube style after I explain that it is just a "locking assist" (or whatever) device and not an "auto locking" device. And that care must be taken when lowering and etc.
* Long free climbs where it would be too heavy
* Any pitch where you're tied to an anchor and the only way to provide a softer catch is to let some rope slip.
* Any time when it's cold enough that the moving parts can freeze

I'd also like to add that "panic pull" potential and over-relaxed belayer mindset are not flaws of the grigri itself, as some people seem to imply, but rather types of operator error. This is why I think it's essential to catch lots n lots of falls on a tube style device before making this your primary belay device.
All around a great piece of gear. Five starz.

Excellent for belaying and good for things it wasn't even made for. It hasn't made coffee for me yet, but I'm pretty sure it could do it. I had to go with some other things for self-belaying, but that's not a criticism for this gear....it just means there are other things better for self-belaying.

It's a nice device, except the minor flaw of the false sense of security (like others said before). The "I can't do anything wrong" thinking that it can cause might lead to the mistake of feeding in the rope in the wrong direction, causing the device to fail. If you do that with most tubers, it will either work equally well (if it is symmetric) or just provide less but still enough friction.
Don't buy this hoping to get rid of work and responsibility.