I'm going in the other direction - I've been using Carrara and am currently learning Blender. :) Cycles render engine is definitely more powerful and potentially more realistic, but Carrara's is surprisingly good considering how long it's been since it was last updated and I personally find the tree based shader system easier to work with than the node based one in Blender (that might just be what I'm used to though).

A couple things to be aware of - Carrara does use DAZ content natively, but it tends to lose bump maps and add unnecessary color multipliers to the diffuse on loading, so you have to find them and manually add them back in, so if something has both a poser version and a DS version, it's usually best to try and load the Poser version, except for Genesis/Genesis 2 characters and items (use the DS version for those). Carrara also currently does not work with the latest generation of DAZ characters - nothing after Genesis 2 Male/Female.

Also, I second manleystanley's note about the advantages of using Carrara's replicators. I think you'll find that Carrara's replicators are not quite as versatile as instancing in Blender, but are much more memory efficient. I regularly see people crashing Blender in tutorials on a number of replications that Carrara could handle easily (I have a Carrara scene with over 1,000,000 replicated trees and about 500,000 other replicated objects in it and the view slows down a lot but the memory use isn't too much more than just a dozen actual trees would be - I'm not sure you could do that in Blender).

Exporting Carrara's trees might be more trouble than it is worth - it works fine, but they make for crazy high poly OBJs. If your intent is to end up in Blender then have you tried playing with Blender's sapling generator? It's an included add-on, you just need to turn it on. Here's a nice video showing someone using it: https://www.youtube.com/watch?v=WlRF5S0aHwU