@lewm , there are 4 degrees of freedom (movement); horizontal, vertical, axial and torsional. Theoretically a tonearm should only be able to move in two of them, horizontal and vertical. Movement in the other degrees will cause distortion of one type or another. Axial movement would cause something like wow and flutter. Torsional movement would certainly increase stylus and record wear and depending on it's resonance frequency, distortion at some level. Tonearms have to be as stiff as possible in the last two degrees to maintain proper geometry. It is bad enough that an arm operates in arcs, warp wow can be painfully obvious. Stick a dime under the edge of a test record and play a midrange tone. The change in pitch is obvious. An arm that has it's vertical bearing at record level will be a little less obvious. This is why Tri-Planar and Schroder designed their arms the way they are. The 4 Points are another example. Reed also does this with the 2G. I could own any of these arms. All of these arms are also neutral balance arms. Tracking force does not change with vertical motion. Most arms are static balance.
Anyway I chose the Schroder CB I guess because it is a favorite of many whose talents and opinions I respect and I like Frank's design mentality. His arms do everything an arm should do but they look so simple, elegant.
As for unipivots, they are a simple cheap way to build a tonearm. The two best unipivots, the Graham and Basis arms have been redesigned and have mechanisms to control torsional movement. Graham uses opposing magnets and Basis added a weird second bearing that stops torsion in one direction. The offset counter weight is then adjusted so bearing contact is maintained. It is really not a unipivot anymore. It is a bipivot. Adding lateral weights just lowers the resonance frequency. Good preloaded bearings are expensive and machining becomes critical as the bearings have to be aligned perfectly. It takes a very skilled person or a very fancy machine. Rega and Pro-Ject arms are a great value because those much bigger companies can afford the very fancy machine. I would take a Rega arm over a unipivot VPI arm any day.
Can you imagine the arrogance of SME limiting their tonearm sales to their turntables! In order to get one of their arms you have to spend a fortune on one of their tables. They are great tables but let's face it, a great value they are not.