I admittedly don't actually know a whole lot about all the different lines because while I really liked Aussies, and wanted one eventually, I didn't really plan on getting one when I did. So I didn't do a lot of research on lines... I just liked the litter, what I'd heard of the parents and relatives in their pedigree, and the values of my breeder and what she does with her puppies. Now I'm in the process of learning more, because I love this breed and want to be way more involved.
I think there are a fair amount of good Aussie breeders out there and it's good to explore options!
Since I can't really comment on lines specifically, here are my experiences with the two different 'types'.
I've never met any working dogs from actual working breeders that anyone's ever heard about. The ones I've been around are just from ranchers/farmers who bred their dogs that they use for stockwork. I didn't like those dogs - they were very sharp, very reserved, serious, not very tolerant of other dogs and just honestly seemed to have a short fuse, for lack of a better word. And in a lot of ways they reminded me of Border Collies, but I wouldn't doubt that they likely have BC in their line somewhere.
I've been around some show line dogs who were way too overdone for my taste. Dripping in coat that is not easy to care for, very laid back, slow and just kind of dopey I guess. But I wouldn't say that's the majority. Most of the dogs I've been around are much like Journey. Happy, goofy, bouncy, focused when working, driven, lots of energy but with good off switches, etc. I do notice that some are very soft, though, and give up easily/almost shut down if they do something wrong or their owner doesn't stay super excited the whole time when training. Which is not a trait I prefer in a dog.
I think the best thing to do would just be to try contacting breeders whose dogs you think you might be interested in and just ask questions as far as the things that are most important to you go. Like...
I wanted a very driven, high energy (with an off switch), happy, joyful, middle of the road (not hard or soft), versatile dog capable of handling anything I asked of her, hopefully wouldn't have a huge heavy coat, and had good health and longevity and stable temperaments behind her. A dog that was likely to grow up and be friendly with people and other dogs, and really, just an overall "take anywhere, do anything" dog. I was also seeking a dog that could put up with my sometimes short temper in real life (not in regard to the dogs - but like the stupid jar of pickles I got mad at last night because it wouldn't open haha. I didn't want a dog that would be scared if I got mad or frustrated with something - I need a resilient dog). So yeah, the point is all of these things and the questions I asked are what lead me to believe that a puppy from Journey's litter should suit me. And I got pretty much exactly what I wanted, more than I even imagined possible. And I got it in a show line dog, which a few people in person when they heard about my impending puppy tried to warn me would be a fluffy, useless couch ornament.
Just talk to as many people as you can. I didn't quite do that with Aussies prior to getting one, as like I said, my timing with the breed was kind of a whim, but I did it with another breed and learned so, so much. Way more than any website or even a dog forum could tell me. Facebook is an excellent tool nowadays for getting in contact with owners of a breed you're interested in, and puppy owners of a particular breeder. And most people will brag about their dog and breed and tell you all the good things, so sometimes it's also helpful to ask about any traits they don't like or wish were different too so that you get the whole picture.