Patches, the dog in my avatar is my "I'm never getting another dog" dog. We lost our Dalmatian and I swore I'd never be able to love another dog without comparing him to the one we lost. Nine months after losing him, a patient came in crying; she found a part Dalmatian starving and tied to a tree stump--would I please take him. I called DH and said go to Walmart, get dog things, we're getting a dog (this was Christmas Eve.) He was not happy to say the least but I told him we're getting this dog (we make all big decisions together but not this one!) Got Patches who was 20 lbs, missing part of an ear, has a chunk out of his tail, and no hair on one leg. Brought him home-no accidents, LOVES to eat actually dances when we're putting food in his bowl. He's now at normal wt of 65 lbs and he fit in like he was born here.
It was much easier to get an older dog (no clue how old Patches is).
I like the idea of spending time with a few dogs to see how they react to you and others. I didn't have that opportunity and just got plain lucky.
Rescued dogs do come with some baggage: mine is deathly afraid of loud noises, gun shots, hammers, etc. Talk to the rescuers and ask about stuff like that.
Good luck and bless you for doing this. I thank God everyday for Patches--I can't imagine my house without him.