Have a feeling that Cinema4D's unwrap is great, I've only used trueSpace as a modeler/UVtool (now free since development has stopped) and there it's a lot of manual labour and no "relaxation" of the uv coords.
And I can't say how the future will look but so far ZBrush has been a very "cheap" investment for me since upgrading from zb2 to zb3 and all plugins so far has been free for registered users.
( Actually Maxwell has also been like that so far since I bought it when they had the offer "get Mw1.7 now, upgrade to Mw2 for free"

)
Will you put these sculptures on a floor or table? Just a surface below with a very rough surface/reflection would look really nice.
My Photos and CGI work:
http://www.flickr.com/photos/larsmagnusson/
Software: ZBrush4, MaxwellRender2.5 64bit, trueSpace7.61, PhotoshopCS4ext 64bit
Hardware: Core i7 980X, AsusP6T Deluxe V2, GeForce GTX 480, 24Gb DDR3 1600MHz
OS: Win7 Ultimate 64bit