ill give you my opinon but its not based on brands. A 600 yard range finder is about useless. Most will only really work to about 300-350 yards reliably and most rifles used in open country are flat enough shooting that ranging isnt nessisary. Personaly i wouldnt waste a dime on one that didnt have at least a 1000 yard rating. At least then you can range out to 500 yards or a little more.