Olive Garden - Haven't eaten there in 19 years. I got nothing besides salad and breadsticks.
Outback - Childhood staple, have gone there a few times in the past couple of years with friends and family. Love their Caesar salad (their dressing and croutons are the bomb) and, of course, the Bloomin' Onion. Quality hasn't really changed much overtime.
Red Lobster - I've only gone there once or twice, though I've enjoyed the take-home mix of their Cheddar Bay Biscuits on more than one occasion. Sad, since they're really the only thing worth getting there.
Cheesecake Factory - Gone here more than Red Lobster, less than Outback. Expensive (and most often, crowded) as hell, but I haven't yet had a meal there that I didn't like.
PF Chang's - There was a point where I really liked this chain; then they must have switched suppliers or something because all their food got really subpar in terms of both portion size and overall quality. There's better (and cheaper) Chinese-American places in my area.
California Pizza Kitchen - Really love their frozen pizzas, but I haven't stepped foot within one in at least a decade.
Red Robin - My feelings on this chain are the inverse of PF Chang's; they were pretty mediocre when I was a kid, but in the last few years they completely reinvented themselves, improving the quality of their food in a major way. Recently, they've taken off an item or two that I really enjoyed (Marco Pollo ;_; ), but overall, Red Robin is still the best burger chain around for its price point.
Of the seven, I'd go with Outback just due to the uniqueness of some of their offerings, and how well they've held up over the years. Red Robin comes in at a close second.