Casual and comfortable, Yen isn't a see-and-be-seen place, but it sure hits the spot when you're craving some sushi. And for the record, it does have quite a bit more ambiance (read low lighting, muted decor, and pillowed benches) than several other places of its size and relative location.
Let's get to the important stuff: the food. I've been here a few times and never had anything less than fresh, quality fish. Toro, Sake, Hamachi, we've had it sashimi style and in funky-good rolls. Unagi and Tuna tataki are top notch, too. Among my favorites are the Sunset Roll (crab mix and avocado roll topped with salmon, sliced lemon, and rooster sauce), and the heart attack (think jalapeno poppers stuffed with seafood).
They have great happy hour discounts on drinks and food, but for me the hh menu is a little one-dimensional with mostly tempura items. I love me a deal, but I would suggest mixing in a few regular menu items to round out the experience.
Oh, and don't dine here if you're in a time crunch. The service has always been courteous, friendly - and beyond slow. I usually enjoy a slower pace, but it's nice to have a full water glass and a drinky-poo to help pass the time.