In my experience, yes, they're nuts.
It obviously depends on your bloodline you're buying into. Show lines tend to be more timid, much quieter dogs in my experience. The working line (primarily bitework/sport) are nuttier, although still naturally aloof and a bit shy, they should maintain a strong air of confidence about them.
I prefer a dog with a bit of balance, I want over the top drive and desire and I will sacrifice some "ease of being a pet" for an phenomenal sport dog, however if I can get both I'll take it.
Neither of my two ever settled down, Sloan still doesn't have an "off switch" but we don't mind. She's a blast of a dog, always ready for more and always throws her heart into it. She recently jumped 25 feet at a dock dog event, for a dog that weighs about 45-48 lbs on a good day, that's pretty dang cool. She's also exceedingly fast, anyone who has seen her in my flyball circles has begged for us to run her. Unfortunately, with all give and take, she has potentially dangerously strong prey drive and after a few recalls where she jumped other dogs we decided to pull her from the sport. She's currently going for her CD and her BH this winter and should be totally ready for her IPO 1 early next year before her second birthday. I am also training her in agility, Denis (my boyfriend) is her handler for everything else, and she's showing a ton of promise.
Backup is a bit more of a dingbat. He's lucky he's a hilarious dog. He is not what I would call a thinker, he's smart don't get me wrong, but he moves too fast for his brain to react most of the time. He's also a spinner, if you can't handle dogs that pace and spin and pant frantically then this isn't the breed for you. Not all dogs do it but the likelihood is high. Backup recently, as I said, has started to learn how to calm himself a bit and relax when I'm not moving nor touching him. Backup is a great counterpart to Sloan in many ways, where he lacks some of her thinking he benefits from not over thinking things. Things that confuse or spook her because she's over thinking them are like second nature to Backup. He has done very well in herding (where as Sloan tried to eat the goats) and in flyball he's a dream by way of he doesn't look at other animals as anything important to chase or fear or anything. He's also one of those dogs who will jump first and ask later, training him Extreme Vertical has been a breeze where as other dogs really don't understand it. We're hoping the same for Backup as with Sloan, a CD and BH this winter and his IPO 1 early next year (if we can ever get a solid Hold and Bark on him).
I don't recommend the breed to very many people because honestly they're a lot of work. They're fabulous dogs but you have to enjoy them for what they are. At 5 am Sloan begins to stir, she paces her great dane sized crate and wags her tail clinking every bar. She goes side to side and squeaks and whines. Once let out she shoots out like a bullet and slams into whomever isn't awake yet. She then runs down and up the stairs until you catch up and then off to the toy bucket and the day continues as such, throw this, tug that, lets go-go-go-go. She's a very interactively dependent dog. Backup is content to grab a toy and spin in circles. We love every minute of it and have a great sense of humor with them.
We chose not to cap any drive as puppies and enforce any off switches. We may do differently with our next puppies but I'm not sure, it's not *that* bad for us but it may be god awful for other people.
I could go on and on describing the other mals we train with and know as each are a bit different and have their own traits but over all the general fact is you'll lose sleep, you'll learn to laugh or you'll cry a lot, you'll get bitten (a lot) and you'll find yourself obsessed with the breed, they're addictive.