In my experience, the undersaturated look is the result of leaving the gamma correction at the default of 1.8.  It can be turned off (expecially for dark, contrasty noir type images) or reduced.  The above image was created at a setting of 1.4, and it is still pretty light due to high sun light value.  This was rendered with full lighting (4 bounces) and that is, of course, also adjustable.

You are quite correct that Carrara can be washed out using default settings, however, this is easily overcome by tweaking.

Regarding landscape abilities, let me start by admitting to absolutely no knowledge of Vue, so this is not a comparison.  Carrara has a pretty funky terrain editor, but you can import a grey scale image and use it as your base reference.  One thing I really love is that you can cause multiple instances of any object (trees, plants, buildings) to follow a terrain.  This allows you to create a forest sprawling across a hillside with a few clicks.  There are some excellent tree specimens available from third party vendors.  To further enhance this, you can create a mask on the terrain so that the objects stay in certain boundaries (think no trees in water or roads).  Also, you are not limited to Carrara native plants, I use poser trees and plants frequently.  When distributing them, you can have them randomly rotated so they don't all face one direction.  Lots of fun!

With respect to the OP's desire to use Poser/DAZ content, Carrara allows you to simply attach multiple runtimes to it's browser and immediately import content.  I have to say, after using Poser for years, it amazed me that there is rarely a delay or "deep search" for textures.  If it can't find something, a window pops up which lets you browse to the appropriate folder and point to the missing item.

Finally, the ability to take an object and quickly modify the mesh is fantastic.

Klebnor

Lotus 123 ~ S-Render ~ OS/2 WARP ~ IBM 8088 / 4.77 Mhz ~ Hercules Ultima graphics, Hitachi 10 MB HDD, 64K RAM, 12 in diagonal CRT Monitor (16 colors / 60 Hz refresh rate), 240 Watt PS, Dual 1.44 MB Floppies, 2 button mouse input device.  Beige horizontal case.  I don't display my unit.