[mumofstig]

I'm thinking of getting one of these for the plot
http://www.mr-fothergills.co.uk/seeds-plants-gardening/83045P/blackberry-serbian-cacanska-bestrna-fruit-plants

the write ups are impressive, but personal recommendation is always to be preferred, so

has anybody grown it?

[arugula]

Thornless brambles. Sound good.

[compostqueen]

I have a bought blackberry (name escapes me) but I have to say I think the wild ones in the hedge bottom yield far better tasting fruit than my bought one 

[mumofstig]

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

[compostqueen]

My bought plant is now really beginning to crop after a very slow start. It's some years old now but has never really delivered.  The fruits I can only describe as salty!  I have no idea why they should be so

I am fortunate in that I have hedges at home in which I've left brambles as I like them so much    When I walk the dogs I pass hundreds of brambles and the council keeps them under control but only cuts them back to the pavement so we still get plenty of fruit.  There is a public washlands area near me and it's covered with brambles and is a paradise for pickers.  You still see lots of folks brambling here which is great    We have some public cooking apple trees too so it's not difficult to go out and round up some pie material   

[SG6]

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.