Here is a link to a recent thread that should be helpful:
http://www.quiltingboard.com/main-f1...m-t206574.html
I don't know enough about the Tiara to comment on it. However, buying a longarm is a lot like buying a car -- you want to test drive different setups to find what feels most comfortable to you. Quilt guild shows are a good place to do this. Of the ones I have checked out, the Innova is the one I like the best. If I ever upgrade from my Voyager 17/Hinterberg frame setup, it will probably be to an Innova.
Edit: Keep in mind that it's not just the machine that's important; it's also the frame, and how the two work together.
It's a good idea to spend a year researching before investing in a longarm. The homequiltingsystems group at groups.yahoo.com is a good one for gathering information. It's a large, active group of people with setups ranging from the very inexpensive to top-of-the-line professional. Lots of good info there.