If you want to easily use Poser (DAZ) content the best route would be to go with C4D and InterPoser Pro. InterPoser Pro will allow you to use your Poser runtime with C4D, and retain all the morphs and bones. With Modo you will need to export your figure to obj and import into Modo. All morphs will need to be imported/created individually.
One word of caution though, in order to have the same feature set you currently have in Carrara, You will need to get the Studio version of C4D ($3,695). True, this will give you a lot of features not found in Carrara, but that’s quite a hefty price tag unless you have some really good reasons for moving up to a pro application.
The renderer in Modo is very nice, and very fast, but you’ll have to deal with a less than ideal import routine to use your DAZ/Poser content in Modo. Unless you have a very specific need for some of the advanced modeling tools (or other tools) in Modo, it really isn’t an ideal environment for using DAZ/Poser content.
Carrara’s renderer is really extremely good for the price. True, it hasn’t gotten a lot of love since DAZ purchased it, but it can still produce fantastic results. If speed is an issue, with the money you spend on C4D you could get a dual hex or octa core CPU rig that would make Carrara renders fly. If you plan on using Lux, then the machine I just mentioned would definitely serve you much better than getting expensive software. In fact, if your really interested in using Lux, you could export to obj (like you would have to with Modo), then import into Blender and use Lux (or Cycles) to render. In fact, if your looking for another application that has more features and faster development than Carrara, you should take a serious look at Blender.
Both Modo and C4D are fantastic applications, but Modo isn’t Poser/DAZ friendly, and to duplicate the capabilities of Carrara you need to spend a lot on C4D (plus the cost of annual maintenance), and get interposer Pro. If your goal is to render Poser/DAZ content, then it’s hard to beat Carrara. Carrara can get outstanding render results with a little work, and Carrara has integrated landscape tools that neither C4D or Modo have.
I would strongly suggest that you look at what you really want from your 3D tool set, and then go through the tools available in Carrara, Modo, C4D, and Blender. If faster/better renders is your main goal, then I would strongly suggest you learn how to get everything you can from Carrara first (most everything you learn about lighting, materials, and rendering can be transported to another software later). Lux Render is very nice, but you can achieve very similar results in Carrara - and the render times will also be equivalent (loooong).