It is all about the number of nodes, a spline curve node being equal to about three ordinary nodes of data because of the bezier control.

Polylines DO manage more data that ordinary lines do since they understand enclosed shapes, stretching like fills do.

None of these issues matter much, but for redraw speed, you always want the least nodes. If it takes more than an augenblicke, you want to consider reducing nodes.

For instance, I often bring in Onyx Tree Pro trees that have every leaf drawn in plan view. These symbols take a few seconds each to redraw, so i substitute a circle in the symbol. The dance of the thousands of overdrawn leaves are morbidly fascinating. Sort of like when I cut open a golf ball and made the rubber bands inside dance with my razor knife until hitting the liquid latex center. What a mess.

My approach to manage excessive nodes is layer control, not node reduction. Isolate problem elements - only view those layers when needed.

If you are worried about using splines as label markers, you need a stronger graphics card because nominal drafting issues should not be a problem with a modern machine. They ARE worth the effort, tho, being so pretty.

Most slowdowns are caused by trace references and other gross redraw problems.