Just seen Cloverfield, in the comfort of my own private cinema (and portable too) and its not bad at all, the background couching (er, COUGHING!!! Damn my half-addled brain) of some unnintentional co-stars ad-libbing their lines didn't detract too much like it would have done had it been some medieval romp!
On the handheld, you do lose some of the detail, but the smaller screne does also remove some of the imperfections, which isnt too bad.
Will see it when it is releazed over here tho.