I'm shopping for a kitchen faucet for my one and only kitchen sink. I'm unsure of whether to get pull-out or pull-down. Also, I know I want a spray control that will stay on without holding the button. One faucet I'm considering is the Grohe Ladylux Plus -- it's a pull-out, and I really don't know what the advantage or disadvantage is over a pull-down model. Help me with my selection, please. Thanks!