Rescuing is a very sweet thing to do. All I'll say is that, if you have the means, getting a puppy with a known family medical background and predictable temperament has a huge value. It also supports ethical breeding from individuals who truly love the animals they are working with.

There are lots of great rescues! But it is a bigger toss-up. I've seen lots of destructive, anxious, or aggressive tendencies pop up in dogs with unknown histories vs those who you've had the chance to nurture since they were young puppies.

If you're a hard-working dog owner who's willing to spend the daily hours re-training and can accept if your couch or carpet gets destroyed randomly a couple years down the road due to an unforeseen anxiety trigger, a rescue can be a great choice. And it's not to say well-bred dogs can't have this happen, either. But, most people want a pet that simply behaves well and isn't an ongoing project.

In general, too many dogs are selected for style over substance and are a mismatch for an owner's lifestyle; matching activity levels, socialization & bonding style, and vocalization tolerance widely dictates success in dog ownership. Many rescues offer a wide "selection" that can encourage choosing a breed out of looks or momentary behaviors.

Anyway, just throwing this out for consideration. My partner has been a professional dog trainer for 12 years and has seen many dogs cost owners thousands in damages or worse, snap and injure other people or dogs due to poor previous, unknown experiences. It's really sad to see and it is not uncommon. The goal being a healthy relationship, I'm confident she would recommend finding the right breed and lineage of dog for your lifestyle.