Some interesting views.
I agree with both opinions. Mainly because I've used both scenarios. DVI fibre distribution and the image-pro to SDI/HDSDI

Its a good discussion point - but the is NO definitive answer.
WHY?
Because it depends upon the requirements of the production.

I mulled over the question of what to include in a new catalyst rack for quite a time - one answer I arrived at was just to install 2 x DVI DA's - then Ive you the choice of adding either image-Pro or DVI-fibre distribution in a small rack on top, depending upon the production requirements.

Every job I do, the distribution requirements change.

One thing to note though, that I didn't see mentioned above, is processing delay. Image-Pros (and other scan converters) will inherently add a few frames delay to the signal. If you then add in the OB truck and LED screen processor - you wont want to be putting a live closeup of your singer on the screen for too long! Delay in live performance and TV work is a key consideration.

So - Im going to join jason on the fence too - but my feet are on the DVI-fibre distribution side when possible...

Simon