I wanted to compare a side-by-side render of Terragen 2 and Vue 8 using similar render settings.
Vue 8:
640x480
Render Quality = Final (Internal Render Engine) Raytrace = Yes 
Preset Sky = Daytime
Preset Procedural Terrain, Rocky Desert (Material Preset, Stone Rubble)
EcoSystem = Bulky Conifer 
Render Time = 11:30
Terragen 2
640x480
Quality 0.6
AA 4
Fractal Terrain (Default) Fractal Color Shader, Displacement Amplitude  0.5
Low Level Cumulus Layer, Edge Quality 35, Samples 64
Object Population (Tree) = Xfrog, California Red Fir 
RayTrace Objects = yes
Render Time = 13:47  
Computer Configuration:
HP 
AMD Duel 2.8 GHz
4 GB RAM
nVidia GeForce GTS 250 1GB memory
Windows Vista Ultimate, 32 bit
Voice your Opinion.
Marc