Sketchup has the more friendly Interface user that you can find!
(we can say Moi is the SketchUp of the nurbs! so...
If you use a tablet you must have something for replace the Middle mouse whell of the Zoom in/out !
All plugins shown follow are free! (There are maybe 2 000 to 3 000 plugins! ;)

About curves you must use a special Plugins "Bezier Z" by Fredo6 for create curves like Moi Curves (even of course it's not nurbs! ;)
here only one icon function (see the tool barr ;)


About animation : natively there is automatic animation of camera beteween scenes ! And animation of Plane section!
So very efficient!



About traditionnal animation like Blender TimeLine etc... now you can with Animator by Fredo 6 again! ;)


You have also "Physic animation" with MS Physics


About organic inside : you have 2 Plugins (not free) Artisan & SUbDiv
http://artisan4sketchup.com/ by Dale Martens
http://evilsoftwareempire.com/subd by Thomthom

A free one but very very basic
Subdivision Loop http://www.guitar-list.com/download-software/sketchup-loop-subdivision-smooth-plugin

You have a free one (Not subdive) Organic by Patch technic by Thomthom


You have also organic like "ZBrush Sculpture" but it's not the first objective of SketchUp who is a Box Modeler! :)
Sculpt Tool by BTM http://forums.sketchucation.com/viewtopic.php?f=180&t=20781&st=0&sk=t&sd=a&hilit=sculpt#p174501


I believe that you have better way for simple organic : make it inside MOI
For complex organic use free ones like Rocket 3F, Wings3D, MeshMixer ...exotic like TopMod, Neobarok...
or the very powerful for real organic Sculpture Sculptris : http://pixologic.com/sculptris/ then export Import inside SketchUP!
by OBJ formats!