[geoffc]

This is way late to the conversation, and I'm not an expert at FastTrack at all, but I did make this exact decision (and considered several other options as well).

My main deciding factors in favor of OmniPlan were:

Ease of use -- I just found working with the demo of OmniPlan easier.

Affordable -- I ended up buying it myself, rather than try to talk my boss into buying it.

Doesn't look awful -- all other project management software I saw looks terrible. The bars in the Gantt charts in FastTrack and MS Project look like they were rendered by Windows 2.0.

Reasonable web exports -- several tools do this, so it's more that OmniPlan did a reasonable and simple job of it than that it was superior.

I'm going to post a small improvement to web publishing in a moment here, so look for "improved web publishing"