A polygon mesh or unstructured grid is a collection of vertices, edges and faces that defines the shape of a polyhedral object in 3D computer graphics and solid modeling. The faces usually consist of triangles, quadrilaterals or other simple convex polygons, since this simplifies rendering, but may also be composed of more general concave polygons, or polygons with holes.
The study of polygon meshes is a large sub-field of computer graphics and geometric modeling. Different representations of polygon meshes are used for different applications and goals. The variety of operations performed on meshes may include Boolean logic, smoothing, simplification, and many others. Network representations, "streaming" and "progressive" meshes, are used to transmit polygon meshes over a network. Volumetric meshes are distinct from polygon meshes in that they explicitly represent both the surface and volume of a structure, while polygon meshes only explicitly represent the surface (the volume is implicit). As polygonal meshes are extensively used in computer graphics, algorithms also exist for ray tracing, collision detection, and rigid-body dynamics of polygon meshes. AS QUOTED "http://en.wikipedia.org/wiki/Polygon_mesh".
It is quite apperant that most people dont understand how mesh works I will clear things up for you Mesh will not interupt your game, it is in some sense more dynamic than primitives used in sl and it allows for more complicated math than a sculpty! the Mesh support mostly depends on the processing power of the server and the render of the mesh within your viewer, in most aspects mesh will render faster than the standard sl sculpty! The major advantage to mesh is greater than most of you can imagine and I really dont understand why there are any complaints about mesh, for one a mesh does not limit you to the detail that you can put into your creations where as the limitations we have had in SL have. To sum it all up we will be looking at a more perfect SL, although I havnt been involved with the development team I am well versed with mesh as I have been doing CAD since 93' I would assume that the biggest issue with mesh would be in the scripting and physics So to sum it all up as far as rendering a mesh in SL is not the issue but rather how the mesh interacts with the physics engine, and it is also my understand that the weight of the mesh is going to determine the prim count as to all respects this is the most desireable method of measurment but in reality the final determination of a prim is performance and server cllock time as well as bandwidth hence the method of selling internet services is measured in bandwidth, rest assured your mesh will render much faster as well as be more detailed than you can ever imgine with a sculpt!
Should you need more information about mesh feel free to contact me Stang Zeplin, hopefully I can help you discover the limitless possibilities you can achieve with Mesh!