Sandy has said just what I was going to say. Some rescue dogs will be aloof and distant all their lives. If you opt for a rescue you need to make the commitment that the dog has a home and will be accepted for who he or she is, not expected to be what we might like a rescue dog, or any dog, to be. If it is important for a dog to be a certain way, it is a better idea to get a puppy or young dog and work to shape it to what you'd like that dog to be.
And while it sometimes is true for some dogs, it is simply not true that all rescues will love you more, bond more closely, or think you are the most wonderful person in the world. Some will remain mistrustful of people most of their lives, and some -- most -- come with some type emotional and behavioural baggage that may take months to years of work-- or just acceptance and management. That is why they tend to come into rescue in the first place. The situation is rarely only that the family just had a baby, or doesn't have time. Those are usually code words for "we never had time, never trained this dog, and now he needs some work and we don't want him."
Does that mean these aren't great dogs? No
-- it just means to be realistic about getting a rescue and realise there will generally be at least some remedial work to do on training and behaviour. They may well be hard work, as challenging as a new puppy. Sometimes the new owners are a lot more needy than the rescue dog and need to feel they are doing the dog a huge favour and changing its life and therefore let it get away with all sorts of things, making it worse than it might have originally been-- you end up with a dog with severe separation anxiety created by an overly dependent owner needing to bond with the dog, not the other way around! Dogs like children tend to do best and be happiest when they are given structure and some independence and allowed to be who they are rather than smothered, overly fussed over and catered for, and expected to be what they are not.
Most rescue dogs are not serious problem dogs at all, though and just have minor issues (that will still take commitment and understanding!). Most rescues including me are primarily rehoming other people's dogs that have not been abused, mistreated or overly neglected and so will fit in pretty easily.
. Even the puppy farm dogs I've had in, excepting one -- Megan who is now in Scotland -- were not terribly neglected and weren't maltreated. Megan herself bounced back very quickly BUT -- the important thing is that she like all the other puppy farm dogs I've had in, was obviously someone's pet before they ended up as breeding dogs. It is a lot easier for dogs like this to revert back to their old selves than some of the long term, lifetime puppy farm dogs of the type you see at Many Tears rescue, or Lucky Star in the US, to ever become normal.
So what you are likely to get with a rescue is simply a former housedog being rehomed for some reason and as such they fit pretty quickly into a new home.
Actually one of the smallest worries anyone has adopting any rescue dog of any breed is 'bonding' -- probably one of the most meaningless concepts as almost every dog alive will bond immediately with at least one person in a new situation and often all of them. I have rehomed well over 100 cavaliers and helped with general rescue as well and never once has a dog had any problems enjoying its new family.
The only issue I have ever seen with bonding is when people get two puppies together and they grow up more interested in each other and too closely bonded together and interdependent -- as they are rarely managed properly and given lots of independent training and care, and thus have serious anxiety issues if they actually have to be separated even for a vet stay.
More of an issue and sometimes, a problem, is the new owner's assumptions and expectations. Dogs generally end up being the dogs we want because we as owners give them time and training. Dogs end up not being the dogs we want for lack of same. At the same time all dogs have different personalities and will have been shaped by their life to date, so all of that goes into the pot. Rescues are not much different most of the time from taking on any previously owned dog.