In my area, many nurseries and even some individuals are selling thornless blackberry bushes. I think these can be very nice while you're picking, but I would choose the conventional thorned variety and here is why.
I can't take credit for the scores of blackberry bushes which lace the trees and the periphery of the wooded portion of this farm. About eighty years ago, the aunts and uncles of the gentleman from whom we purchased this land, planted blackberries. Blackberries are one of the few things that really tend to do well in Virginia clay, which we have in abundance here. The result is a literal moat of briars around the periphery of fifty acres of the farm, and in Spring, the motherlode of blackberries. Of course, all of these blackberries atract black bears, who incidentally eat the branches with briars, leaves, berries and all, as if the thorns are nothing ! There are still plenty of blackberries for us, and the periodic natural grooming of the blackberry bushes which grow to be quite large, is something for which to be thankful. This way, the blackberry bushes stay where they are, and do not invade more places on the property than we want them.
Both bear and deer seem unimpeded by the blackberry thicket, however that is not true of people. If we were to traverse a region of the blackberry thicket, and I did once, it requires quite a hit of work using a sharp machete. Too often while you are cutting, a long arm of the blackberry bush springs back whacking you and leaving quite a sting sometimes with some blood loss. The blackberry bushes when they are not producing, are a natural fence which will effectively prevent human beings from trespassing into areas we do not normally use. In places it is truly impassable. The actual entrances are gated, and monitored.
When the blackberries are producing, you have abundant blackberries for immediate eating. They can be fantastic in cereal, oatmeal, and in my favorite, a blackberry and apple pie. The remainder can be washed, and quickly frozen on a cookie tray, and then when each blackberry is frozen, bagged in freezer bags where they last very nicely for two years. They are also fantastic in a blackberry and apple crumble covered with British Bird's custard. (You can make your own custard, but I take the short cut and buy the custard mix)
Blackberries are very healthy and are filled with potent antioxidants. They are worth planting and well worth the harvest.