Blackberry plants tend to produce more fruit than raspberry plants. I think brandywine (purple) raspberry tends to be pretty tart, from what I have read. Royalty or Glencoe are less tart (fresh eating) purple raspberries. Most black and red raspberries are sweeter in taste but usually do not produce as many berries as blackberries. You may want to do a little research on your climate to determine which plant variety would grow best there. Wal-mart and other large general retailers often sell plants that are only marginally hardy (adaptable) to your climate.

Blackberries: Cutting back during the growing season will cause the remaining cane to branch out and that increases berry production next year. You can prune at any time to a size that is convenient for you. In some locations the canes will still be growing in the fall; pruning the main cane then will result in shorter branching or no branching.

i would find a local grower ... or orchard that grows them...and ask them what cultivar they grow... LOCALLY ... my local orchard even sells plants in spring ... though i love wallyworld ... i would not rely on plants shipped.. in bulk from arkansas ... e.g.: googling : raspberry growers CA ... i found the link below ... getting good cultivars.. really matters for berry production ... pay the money.. to get a good start ... and do not expect much production the first season... and learn all about their biennial tenancies ... and how to prune them ... and do look for EVERBEARING types... they give fruit twice a season ... both of these berries.. are bramble... and can run from horrible ... huge ..... invasive-type plants... that barely berry .... to good acting [blanking on the word i want] .... plants.. that nearly crush themselves with berry production... its really worth it.. to get the right one... ken ps: never met a blackberry that out performed a raspberry .... pps: i have a yellow rasp.. fall gold.. to die for ... and heritage .. same ... i killed off dads historical plants.. years ago.... once i got these .. they grow well in MI ... no clue where you are ... Here is a link that might be useful: link

The caneberry types you mention are not typically sheared, but are selectively pruned one cut at a time. Rasp and blackcaps should be easy to cut through with any basic hand pruner; some erect blackberry types are a tougher cut. All I can say is, my dull 20-year old smallish hand pruner works just fine, if you use a circular motion around the larger canes, scoring or cutting through the outer cane layer by pinching the cane with the tool and rotating the cane or the tool around the cane circumference, they cut through quite easily. It would take brute force or a more advanced sharp tool to cut straight through in one squeeze--many such tools are common.