Contrary to popular opinion, this doesn't mean the renderer needs to work within SketchUp. Often this can be as much of a drawback as a benefit, because you can't carry on modeling when your SketchUp's locked in a rendering cycle for four hours! Also an external renderer usually handles imports of other file formats better. So, what you may like to look for is a few buttons within SketchUp that will help you export (just like SU2KT), or a renderer that supports the SketchUp native format really well. Next, does the export/import process retain lights, cameras, sun settings, animations, and component hierarchy? Does it allow you to merge in parts of a scene or do you have to start all over again whenever you change something in SketchUp?

Also be aware, some renderers require you to own a SketchUp Pro license, others will work with SketchUp for free. Tables 1 and 2 have been split up to make the difference obvious.

You might think Global Illumination is a strange choice, but I'm totally amazed by how many renderers there are out there that don't have this most basic of photo-realistic rendering capabilities' yet market themselves as photo-real renderers. Global Illumination (GI) (or indirect lighting) saves you having to add extra lights all over your scene to simulate indirect light bounce. It's the single most important aspect of getting a realistic render, yet many renderers out there don't tell you that they're just Raytracing (direct light) engines. Global Illumination rendering is slower than Raytracing, but this isn't important nowadays considering the awesome computing power of the most basic desktop PC. Furthermore, most GI renderers have a Raytrace setting too, so you can still use it if you wish (for example, to speed up rendering for an animation).

The tables below have been split into GI and Non-GI renderers so you can be sure all the renderers in the first two tables (1 & 2) simulate GI, and rendering quality will be more or less "accurate".

Once you start rendering regularly you will become more and more aware that rendering is more about time than quality. Once you have the quality sorted out (and you will), what matters is the amount of content (entourage, template scenes, help, and training material) that's available so that you can produce renders quickly and efficiently to schedule. The kind of thing to look for here is large forums, books on Amazon, good phone or email support, and external sites offering entourage and other content. You don't have to access it, just know it's there when you need it. What also matters here is that the major file formats are supported so that you can import stuff you find on the Internet, such as 3DS, Max, OBJ, and DAE.