Album DS is a larger and more complete application than TD, it uses Photoshop working area and is intended for users who prefer to work in Photoshop without creativity restrictions.
Album DS full download is more than 4.5 Gb and Album TD is 250MB.
But Album TD is faster if your design style is “modern”, I mean square or rectangular boxes for pictures, aligned and less use of fusions, retouch, brushes, etc.
Both applications have the Designer (but Album TD has a far better designer), in Album DS you design one sheet and then export to Photoshop this sheet, make changes if needed and finally save with Album DS. In Album TDS you design all sheets and save them, if you want you may export sheets to Photoshop, otherwise you will get JPG files.
Album TD compares, and sometimes surpasses, to the current softwares offered by our competitors, but for a fraction of the price.
Album TD won the 2015 Hot One Award by Professional Photographer in the album design software category, Album DS won this award in 2008 and 2010.
I understand it’s a difficult choice, I would recommend DS if you love Photoshop and like to finish albums until the finest detail; but if you are looking for the fastest tool then Album TD is what you need.