As pnoland mentioned above, you should judge Cycles on the massive amount of work that has been done over the last 5 years by Blender users. Don’t base it on the Cycles4D one!
As a starting point, check out the Cycles demo reels done over the last few years:
Tangent Animation have recently released a full animated feature done completely in Blender and Cycles:
One of my fave pieces done in Blender/Cycles that shows a 100% cg Sean Bean:
You may notice, they are all firefly free As Kai covered, fireflies and noise are intrinsic to a pathtracer and it is up to the user to minimise or get rid of them. In Cycles in Blender, you can turn off caustics as well as bias the glossy samples to minimise fireflies…presumably the same options are in Cycles4d?
It is good to see Cycles finally released for C4D, as it is a very nice renderer with a lovely material system. I haven’t tried Cycles4D yet (waiting for the demo), but from looking at the video, it seems that Insydium have done a great job, especially if you are an XP user. My main reason for wanting it is partly because I already know how to use it( also being a Blender user) as well as being continually frustrated with Octane C4D…mainly with the buginess of the C4D bridge and the terrible material system…No problems with the quality of its’ output, but then you would have to try very hard to get crappy output from any of the pathtracers on the market!
A couple of things that do give me some pause about jumping into Cycles4D just yet is that Redshift for C4D is just about to drop, as well as the current limbo state of Blender development. Most C4D users wouldn’t realise that Blender is a transitional state at the moment and this will effect Cycles development for the next year or so. They have only recently started working on the 2.8 version with big plans to revamp many aspects of it. This could take at least 6 months to a year for a beta to arrive, and although Cycles is its own development branch (and it is used by other commercial packages such as Poser), it is developed mainly as part of Blender itself. When Blender was in the 2.7x series, there was a new version every 4-5 months, but the 2.8 stable version will take much longer, which means any new stable Cycles features could be a good year out. Plus the time that it takes for Insydium to implement them in the bridge.
Having said that, if you are buying it for what it offers now, then Cycles is a mostly mature product. Octane users will find that the material system is much more powerful and logical than Octane, but Octane does have the advantage of the DirectLighting system and is general faster as a renderer (from my anecdotal experience). The quality is excellent on both, and in the end workflow preference is the king. I do think that Insydium should label the displacement feature as experimental, since it is actually hidden away in the current version of Blender, as it is not deemed “production reliable” just yet.
I am also of the opinion that Insydium are being somewhat mean with the number of render clients included with a license, considering it is an open source engine. Won’t effect me, as I mainly use GPU rendering, but it could irk some.
One final link is to the Cycles roadmap with some very cool things coming up in the future, such as Disney BSDF, denoising and light groups. Cycles future is bright :