I have demonstrated my frustration at Eovia, for one, not making its volumetric light cones raytraced effects. I did a render with trueSpace 6.6 to demonstrate that in the Carrara Forum -- a nice particle infested beam through a tinted glass window. I also sent Eovia my opinion on that one -- I certainly see room for improvement. But I have to look at the cost/benefit ratio, and in that respect C5Pro is a winner.

Symmetrical modeling has its greatest value in mechanical modeling (I think you can buy a plug-in to do this in Carrara?). Symmetry in organic evolution does not exist. Organisms tend towards symmetry, but they are not truly symmetrical (in fact, this is one reason why some seemingly photo-quality virtual humans have this hard-to-define artificial quality that gives them away.) At any rate, trueSpace does have symmetrical modeling (called Mirror-Modeler), and I think TSs modeling ability is superior to many applications, including C5Pro. It isnt a huge feature gulf, but I still use TS for some specific modeling needs. As I mostly do artwork, C5Pro is looking excellent for that purpose. Artists who create models on a professional level will not likely consider C5Pro to be a tool of choice for high-end modeling.
From the IT Enquirer C5Pro Beta review: The material editor has changed in as much that you get a tree representation of your shaders by default now, which is much closer to the way Maya works. Its also much easier to understand, although it would still be better if Eovias engineers would take a good look at Mayas Hypershade editor and create a better one for Carrara. Nevertheless, the new material editor is a huge improvement over previous versions. Also, A very useful feature in Carrara 5, and one that I could test in Vue Professional 5 only, is the replicator and surface replicator. In Carrara 5, replicators serve to quickly create identical or non-identical copies of an object. This is done in a much more intuitive way than in Vue. In fact, the only thing that remains the same is the stress the rendering of a lot of copies puts on your processor.
The surface replicator is ideal to populate a landscape with trees and plants, and in my opinion it beats the Vue 5 intelligent algorithm by a margin. A new particle generator can now use metaballs and create fluid and volumetric effects. The editor is easier than the previous one, but it still is difficult to guess how a particle system will look once rendered. Particles will interact with objects and forces in a scene so it should look a lot better. I wasnt capable of seeing for myself as it took too long to render on my G5 DP1.8 GHz. Perhaps the time it took was due to beta debug code still present in the program. On the other hand, a scene with lots of objects and a particle emitter in it, will always take a lot of rendering time.

No one could compare C5Pro on a one-on-one with Maya; however, as a reviewer stated, (not a quote) Maya is appropriate for the movies, C5Pro is appropriate for television.

I never felt that C3Pro or C4Pro were so hot, but Eovia really did roll-up their sleeves and did good things with C5Pro hence my enthusiasm.

Debby makes a good point, Don't forget Terregen 2 comes out next year...it has eco's/clouds & water as well. So really eco's at this point are old news.

Its just how you implement them.