Deciding on a breed

I have been training with a GSD mix lately and am in love with working with him, but for a variety of reasons, getting one is not in the cards for me right now. The thing I love about him is that he is as excited to learn as I am to teach him and he genuinely seems to be having fun with everything I throw at him. I also love the way GSDs are quick in their responses.

Sports-wise I’m most interested in nose work and rally & obedience, but want to try agility and dock diving. We’ve narrowed down our list to a bench line golden, a smooth collie, or a vizsla. All of them meet my needs otherwise and are a fit for my lifestyle. I also strongly considered a bench line lab but struggled to find a breeder locally with more athletic/drivey English lines and don’t think a field line is quite what I’m looking for.

I know to some extent training and lines and personality matter, but if you do sports with one of those breeds - what are they actually like to train? Would you recommend one of them over the others?