Boo is not off leash reliable, but she's pretty darn good about not wandering (I now say this with a grain of caution that I didn't used to have)!
I consider off-leash reliable to be a dog who will come when called, call off of virtually anything quickly, and be bompproof enough that nothing will spook it to the point that it would not come back.
Boo has the first one down usually, but neither of the last two. Her recall is soso - good under low distractions, but virtually non-existent when she is in "prey mode." I cannot call her off of chasing a deer or rabbit mid-chase, although she will come bolting back as soon as she is done with the chase. She comes running when called in the house or yard. She comes slowly trotting (usually) when called and she's outside somewhere else. She can also be a wuss. She is not a skittish dog, but loud noises scare her to the point that I don't doubt that she would bolt if off leash and a gunshot or firecracker went off in the nearby vicinity. She's proven that a loud enough noise will take her little 10 year old butt over a 5 foot fence and far far away.
Until she got lost a few months ago, she had never wandered. Even after that episode, I'm still convinced that the fireworks scared her over the fence, across the highway, and into an area unknown to her. I don't doubt that she would have come back of her own accord in a matter of minutes if she had not been scared and lost. That said, I won't ever have her off leash for any duration of time again (she's still allowed out the front door to go to the car without a leash for example). I would worry too much about a loud "POP!" causing her to bolt and not return. Other than the noise-phobia and prey drive, she has very little wanderlust and so is not a dog that you have to worry about with regard to doors and gates.
I would LOVE to have an off-leash reliable dog. Having a dog that doesn't actively WANT to run away is a necessity for me. Having a dog who can be let outside from the front door to the car or won't cause panic if a gate is left open is also a near must. Having a dog who I could go hiking with off-leash and be able to recall off of dogs, deer, people, and other things would be awesome and a huge plus, but I could deal without it. Having a dog who can heel nicely beside me next to a busy street ignoring all distractions is not at all necessary. (Of course the bragging rights would be nice haha!)