Since I only got one comment about the product, I thought I would post my own review. Remember, I am not a SU power house so my views may be tainted.
I like Spread3D and think it is a good product. The price is certainly affordable. The "Pro" version is only $5/month. There is a free version but your presentations are only viewable for 24hours.
Strengths
Easy to learn - The UI for Spread3D makes it very easy to learn. There are a number of tutorials that seem to cover all of the capabilities pretty thoroughly.
Play/Autoplay - Spread3D allows you to play/autoplay your presentation so that it is good for a kiosk type of environment or if you want to display your presentation in an unattended mode. There are settings for the slide duration and transition speeds. *
Hierarchy - Spread3D gives you full access to the hierarchy in your model that can be manipulated at the slide level. Thus you can control the visibility or some limited animation of a group or component in he model at the slide level. Certainly strengthens the concept of using groups and components in your model in SU.*
Links to external documents and videos - While I did have not yet used this feature, Spread3D allows you to connect to other documents and videos outside your model. You can also create links to external web sites. *
Comments - Again, I have not used this feature (but I did look at it) that provides the capability to allow others to add comments about your model or presentation.*
Rotate/Zoom/Pan/Measurements - You can add buttons to a slide that will allow the user to rotate, zoom, pan and even use a ruler on the slide. This again, is controllable at the slide level.*
Auto Rotate- You can create a slide that will automatically rotate when the slide is viewed.
Weaknesses
Only One Model per Presentation - For me one of the biggest weaknesses it that you can only have one SU fie/model in a presentation. Therefore, if you want to have multiple models included in a presentation you must combine them into a single SU file and scene (you cannot export multiple SU scenes into a single presentation. If you combine models into a single file, you can overcome this limitation somewhat by using the hierarchy to control what is visible on the slide but this could get messy in a hurry* Fonts & Text display - Currently there is a limited set of fonts that can be used in a Spread3D presentation. There are also some limitations on how the text is controlled on the slide (how it appears, color and etc.). However, I have been told that this is being addressed in a future release (no timing on the update). One interesting thing I did discover though is the ability to create a scrolling list/text box.* Performance in IE - One of my presentations would never load in IE. All of my presentation did run smoothly in Chrome (I have only tested with IE 11 and Chrome). Since most of our clients use IE, this could be a problem in making our presentations available via our web site. For a show/convention we can make sure the machines being used have Chrome installed.* No Touch Screen Support - While this is not a show stopper, it is preferred for a show/convention so that the presentations can be used in a kiosk type of environment without having to have a mouse connected.
Bottom Line
Bottom line is that this is a good product that is VERY reasonably priced. It has a lot of good basic features and I have no problem recommending it. Just be aware of the one SU file limitation and you should be able to learn/use it in a very short time. The documentation is very adequate to get you going quickly.