Nope. Should work fine. Just keep in mind that in order to get the best possible picture, you want to make sure you send the largest picture possible to the convertor so that the amount of upscale is minimal. Make sure your box is set to either the 1080i, or 720p HD resolution.
It's a matter of personal taste which of those 2 resolution settings you will like best, but personally I've always thought 720p looked better than 1080i.