I wouldn't necessarily say that it's difficult to find a stable Toller, but there are definitely iffy temperaments out there so it's just a 'buyer beware' thing IMO. And by iffy, I mean that I've met many who are either shy or verging on being shy, and also startle easily to different things. Noises, different things placed in an environment, etc. My experience with Dance and other Tollers is that they tend to react to something before thinking it through first. Just as an example: if there is a weird noise outside or something, all of my dogs will listen for a second and decide if it's worth their attention. Except for Dance, who just barks without a second thought. She's like a little alarm.
One Toller I know, who recently moved away, was my version of an ideal dog. She was appropriately reserved with people that weren't her family or what she concerned to be friends, she was appropriate with other dogs and got along with anyone and anything, super eager, high energy with a fantastic off switch, playful, just an all around nice dog. Very versatile. She'd do anything asked of her, and succeed at it, no questions asked. She was trained using methods I thought were pretty harsh, and while I do feel she acted shut down around her people at times, it was an avoidance thing and not that she was crushed. She was a very resilient, try hard dog. I loved her and I hope that my next Toller is much like her. The only thing I didn't love about her was that she wasn't nearly as goofy as Dance haha. But that's just a personal preference. This dog took everything pretty seriously, as much as she liked to have fun, her version of 'fun' was more about serious work that she enjoyed but did not include goofing off.
I met a whole bunch of Tollers last year in a different province and they were much like the dog I described above, and for a short afternoon I worked in a dog daycare before quitting, two Tollers here for a Toller specialty from the US were attending daycare that day and were awesome and very much like the dog described above. So there are absolutely a lot of very nice Tollers out there. I'd just recommend talking to different owners and breeders and getting a good feel first, rather than just talking to a breeder and meeting a couple of their dogs and jumping in. If you're comfortable, try asking a breeder if you can speak to owners of their puppies if you decide to look seriously into a Toller.
Most of the other Tollers I've known around here have not been like the dogs I mentioned above, but most of them also shared similar heritage, even from different breeders, so I wouldn't doubt if what I've seen is simply genetic to some extent. Dance's temperament, IMO, is not ideal or even correct for the breed. She's very reactionary, insecure and just all around a little bit weird... but so was her dam as I discovered after dog-sitting her, so she comes by it honestly. I haven't met many other Tollers as people shy as Dance, but they've definitely verged on that, and I bet if they hadn't had the opportunity for ample socialization early, they'd also be like Dance (Dance wasn't exposed to much prior to about 13-14 weeks old so that combined with her genetics just wasn't a good mix).
When I was first seriously talking to people about Tollers and trying to learn about the breed, one breeder told me point blank that they are a breed with quirky tendencies and that proper socialization and exposure is definitely needed, moreso than with a lot of other breeds.
I would think a Toller should be able to stand MI winters and hunting just fine, considering their heritage. Nova Scotia is not a warm place in the winter. I'd still be careful in the dead of winter though. A lot of Tollers don't appear to have thick enough coats to be able to tolerate cold waters/weather when wet for very long, but this isn't something I have a lot of experience with. And again, finding a breeder who breeds for natural abilities and working dogs would be something I'd recommend, just to stack the odds in your favour of getting a nice working dog. There isn't really a split in the breed, but there are certainly breeders who do more work vs. show (and vise versa) with their dogs than others.
But anyway: A Toller should be reserved with strangers, meaning aloofness and just an uncaring attitude. They should not be shy, but it seems that some people think that reserved and shy are the same traits. They should be dog friendly in the sense that they aren't DA, but IME, Tollers aren't really 'doggy' dogs. Most of the ones I know don't care to play with other dogs they don't know, and they have no qualms about laying down rules and not allowing any rudeness from other dogs.
They're energetic but not over the top, or shouldn't be. They should have enough energy and drive to go out and work and do stuff, but also be content to not do a whole lot when it's not warranted.
They're very intelligent, quick learners, whether it's something they've learned on their own or something you're trying to teach them. They aren't always the most people pleasing/biddable dogs (some are) and do like to know what's in it for them, but as long as you have the right motivator, you should be good to go. Dance works well for both play and food. She's actually my most hard headed dog and doesn't just do something because I asked her to. She likes to push everything and sneak around and do what she wants. She'd be really annoying to somebody new to dogs I think.
Grooming is pretty easy. Now that Dance is spayed and her coat changed, I do have to brush her a few times a month, but prior to that I rarely brushed her. She's always had a very fine coat though. I like the more plush, thick but shorter Toller coats. They don't seem to tangle and everything just falls off. But even with a finer, harder to care for coat like Dance's, she's not that difficult. Aside from the occassional brushing, I tidy up her ears and feet monthly and call it good.
They have pretty obnoxious voices. They're very high pitched and most of the ones I know don't really bark like a normal dog... it's more like a long, drawn out string of barking. I don't find them to be very noisy dogs though. Unless Dance is alerting to an actual noise (even if it didn't need alerting to), she never barks, and she never barks simply to hear her own voice. She basically only barks when startled or when talking to me (and then she roos adorably, not barking at all).
And this could just be a Dance thing, but she's very busy in kind of a frantic way. When she's learning something, she totally takes the time to think things through, but when it comes to just everyday life, she barely thinks at all. She just does stuff and it's never in a calculated, thought through way. She paces, she prances, she's just kind of frantically busy... it's hard to explain. I've really noticed it since getting Journey, who is always so much more composed and thoughtful, whereas Dance is kind of just all over the place at once, never focusing on any one thing inparticular without a lot of effort.
Other people's experience might differ from mine, and while I have spent a lot of time with lots of different Tollers, I've only ever personally owned Dance (and one other for a short time, who was weird even for a dog, nevermind breed). But hopefully that helps a bit and I'd be happy to answer any other questions.