If you have hundreds of photos, it's worth checking out specialized online services like Pixum or Saal Digital - they sometimes have better options for larger quantities and can do custom formats too. The quality is really solid, and you can upload the photos directly instead of having to get them printed somewhere else first.
One important thing people often overlook: pay attention to the paper type. Some providers give you a choice between matte photo paper or glossy, and that makes a real difference with old vacation photos. Matte just looks more high-quality when the images are older. Also check if you can edit the photos yourself beforehand - old digital photos often just need a bit of color correction to look better in print.