Yes Fuse IDE is an Eclipse based tooling. You can run it without having to use/run any other Fuse products.
Fuse IDE can be used with the Apache products as well, eg Apache ServiceMix, Camel, CXF, AMQ, Karaf etc. So you can develop Camel apps and deploy and run in SMX. And use Fuse IDE to developer, deploy, visualize at runtime etc.
Yes the regular Fuse ESB is being continued as is. We will continue to develop/support/release/etc this product.
You can read about the difference between Fuse Enterprise vs the regular products
Fuse Enterprise includes Fuse Fabric which you can read more about here (community site)
And as well from various links on the FuseSource website
The deciding factors is yours. The products Fuse and Fuse Enterprise and the Apache are all free to use.
The Fuse products has the benefits of having a professional company behind
And we have this little end to end video, which shows some highlights of Fuse Enterprise, and the tooling. Albeit it runs a bit quick IMHO. But its a fun watch for about 5 min.
And I suggest to watch some of the CamelOne 2012 videos, where Fuse Enterprise / Fuse Fabric is being covered. And of course any of the other videos as well.