While I love the Burnside 35, it has unfortunately been discontinued. If you're lucky enough to find one of these for sale at another outlet or used and you're curious if it's worth it, I'd say "yes!" Just make sure you're doing your due diligence as far as knowing what and who you're buying from and that they'll stand behind their product. I'm always very cautious when I'm buying used gear or from outlets that I don't trust. I want you to do your research too!
I am being totally truthful when I say that I am in love with what this lens can do! The Burnside 35 is equipped with slide on the side that allows you to add a vignette to your images. You can add a slight vignette or add a lot. Your choice of depth of field, or f-stop creates the amount swirl in your background. If your subject is really close to your lens they will remain in focus but your background will have that beautiful feeling of circular movement to it!
I love using it with a 20mm extension tube for my macro work. It allows me to get in a little closer and still grab focus. But if you want to get even a little closer, you could try reverse freelensing with it. Please do this at your own risk after researching and practicing inside over a padded surface first! It's risky and you could damage your sensor or drop your camera or lens, or both.
The Burnside 35 has an aperture range of f/2.8-f/16. So at you'll have all kinds of beautiful swirl or you can shoot closed down for very little, if any swirl. Add your own vingette in camera and eliminate the need to create that step in post processing!
As you can see from my gallery, I've even tried intentional camera movement (ICM) with it as well as some video. Full disclosure: I am NOT a videographer, but it was fun to play around with it!