Getting a bump in the release date at this point is fine. What you don't want to have happen is to have all your marketing and promo stuff set up for, say, April, and discover in February that your publisher is releasing your book in March because one of their subcontractors finished part of the publishing process early and the book that was supposed to go there wasn't going to be ready. Because that late, you can't change anything.

It would also stink to get bumped by only a month, so your book hit in December 2006, since, as you know from personal experience, the bookstore staff is not likely to make shelving your baby a high priority. :-)

Those are the only downsides I can see.