Petzl I'd
I've been using the I'd for 2 years now. I don't understand why they haven't caught on more than they have. Possibly the price. They are bomb proof and very well designed. Make sure you get the right size for the rope you're using as the tolerances are very tight. The real advantage is quick lockoff for posistioning yourself, no more transistion worries while changing from ascending to descending, and while descending there is a panic/free fall cam that stops you if your speed is too fast or a free fall starts if you get a little too aggresive in starting your trip down. You can let go of everything on your way down and have both hands for whats needed, try that with a figure 8...... Some don't like the size and weight but that very minor compared to the advantages over an 8.