We are using Spread3D (Pro version) for our business webpage to enable customers and interested parties to watch 3D models of houses and roofs without the need to install (and/or to learn how to use) SketchUp. After the first weeks of experience, we can just state, that it's amazing easy to use (for the publisher and for the user on the webpage), and the feedback from our customers is a hundred percent positive one. Spread3D is just the tool, which we were missing, since we use SketchUp for drafting and designing roof constructions or buildings. Even it's the first version, for us there are no bugs or problems known until now. For us, totally worth the money - and the support is helpful and stunning fast. We simply can recommend this tool 100%.

@hfm said:

...the bigger models stutter across the screen and the walk through feature leaves your camera shaking.

This happens to me also on my notebook (especially when it's connected to my external screen with 1680x1050), but on my office machine (even with on-board GPU!) all is fine, and even in complex models I get fully smooth animation. On both machines is running the newest FlashPlayer, so I suspect, that the FlashPlayer doesn't support some notebook GPUs fully (if so, it's out of influence of the Spread3D makers...).