I am using the DiabloSport Predator. Haven't used any others but I like my predator a lot. It very easy to use and can change your gear ration, wheel/ tire size, and more very easily. Got mine off Craigslist for $150.... Beats the heck out of spending $400 for a new one!
4.10's huh... let me know how your gas mileage is with those bad boys... I have been trying to decide if I want 3.73, 3.90, or 4.10 myself. I'm thinkin i will probably end up with 3.73 because I daily drive this and with premium @ $3.65 a gallon I dont want to go broke because of gas mileage.