Blackberry Cacanska Bestrna

Thornless brambles. Sound good.

They built houses where the brambles used to be  so I'm feeling the lack now it's jam time

Thought I'd bite the bullet and find room for one

Do not have experience of the one you give: Cacanska Bestrna
However do have 2 cultivated blackberry's, Waldo and something else who's name escapes me. Think it is Loch Ness.

They are "different" to the wild ones.
The taste is somewhat different, very nice however, just different.
They tend to throw up 2 or 3 long canes a year.
One of mine will have 8-10 foot canes (Waldo) the other (Loch Ness) will have 15-16 foot canes. Both are longer then implied in the catalogues.

Canes are fairly substantial say 1/2 inch across.

Fruiting is normally quite good, berries reasonably large.

One thing I find is that a cane will have a few berries the first year, then the expected heavy crop the second (normal) year, in the third year a small crop then it dies.

One lazy option is to wait for a cane to die before pruning the bush.

The flavor will be different, but they are nice.