I only thought School Rumble was so so. It was fun at first but it became repetitive for me after awhile so the director doesn't make this a must see for me.
However I am not ashamed to admit that I am totally going to give this a chance for the seiyuu cast alone.
Granted that's not the best reason to watch an anime...but it has worked for me before (Saiunkoku Monogatari).
edit: I never saw Gintama, I know that is a very beloved series so I just want to clarify my opinion on the director's work is not taking Gintama into account. Plus my problems with School Rumble might have stemmed more from the source material.