I've tested quite a few of the various renderers on the market. Maxwell is extremely cool, and extremely slow.
Disclaimer: I do work for Next Limit, I thought best to mention that from the beginning.
I love both XSI (pardon, Softimage) and Maxwell and now with the plugin I think the integration has taken a huge step forward. I´ll post just a few examples to show the speed and you can see why I don´t agree Maxwell is slow. Keep in mind also you should take into account the time you spent setting up the scene and testing different settings with other renderers to try and figure out the best quality vs render time for a particular scene. Human time is more valuable than computer time. You have no worries with flickering, splotches etc in Maxwell and in fact, because it doesn´t render in buckets you get very quickly a low sampling level preview sequence which you can then import into After Effects, Nuke, or Photoshop using our plugins and start working on the post production while the rendering continues in the background. When the sequence has reached a higher SL, you just update it. This is really nice workflow I think, you don´t have to wait for the sequence to finish rendering and overlap the postprod time with the render time.
First example is the Dragon scene, I tried to recreate it as close as possible as other examples posted here, because I didn´t have that particular scene.
Render machine: i7 920 @ 2.67 no overclocking
Time: 3min 30sec
Again this is practically zero setup time, I just added a plane, applied an emitter material to it, and hit render.
Second example is a 121 frame animation (1280x720) with about 3 million particles, with motion blur and DOF. Export time from SI was 1 second per frame. The particles use the new particle primitive in Maxwell 2.6 which renders a procedural sphere to which you can apply any Maxwell material to. I´m posting two different versions of the animation, one at SL 11, the other at SL 15. This is to show that even if there is a little bit of noise left in the SL 11 render, for an animation it will be impossible to see. The compression itself takes away more than any noise left in the render. (I´ll try to upload them to Vimeo too). Plus there are no flickering problems in Maxwell Render, even at low SL. In the worse case the noise can look like high ISO noise when shooting at night. The noise is not "stuck" across frames.http://www.youtube.com/watch?v=Vx9zEiugRD4
(All camera angles)http://youtu.be/ICkcKVPS8t0
(SL 15)Still frames
Render machine: i7 920 @ 2.67
SL 7 (1min 24sec)
SL 10 (4min 42sec)
SL 14 (23min 41sec)
The whole animation was rendered in cooperative rendering on 4 machines:
2 CPU Xeon 1.6 gHz
2 CPU Xeon 2.3 gHz
2 CPU Xeon 3.0 gHz
2 CPU Xeon 3.0 gHz
The SL 11 version of the animation rendered in 55min. The SL 15 version rendered in 7hours 36min.