Love Photo Mechanic since I first tried it while shooting for America 24/7 years ago. It make my digital work manageable.
When I travel, I literally shoot from 500-1200 shots a day, same with many of my projects.
It allows me to ingest the files from multiple cards at one time without worry about overnighting duplicate file numbers, rename, add metadata for my DAM system, cull, sort, rate, rename, and organize my photos, all before I get to the nitty-gritty of processing photos. It's great for captioning & keyboarding, IMO. And it's pretty quick when you've got a bunch of images and a short time to deal with them. It even allows me to organize my video clips since I shoot both still and video.
For me, it's essential and makes the digital process manageable.
It's really a good way to prepare your images for import into Lightroom for some, or like me, to prepare the photos for post processing in Photoshop. In fact, it dovetails directly into Photoshop quickly and easily.
When I need to find photos at a later date, Photo Mechanic also dovetails its search feature into Spotlight for finding my files. This makes them easier to find since a direct search using Spotlight brings up every last file not an image until one fine-tune the parameters.
IMO, I couldn't manage my photography without Photo Mechanic.