... here's one reason among many to give it serious consideration.
I looked around for a long time for fast and efficient 'save for web' routines. I always hated Photoshop's. I tried several standalone applications. All that came close to being useful nevertheless had some serious flaws. I even tried rolling my own command-line-driven tool, a Perl script that calls both ExifTool and ImageMagick (<sigh>: mixed results at best). The GUI app I finally settled on has a UI that takes getting used to. It was working ok but recently I found some of its conversions to sRGB producing a noticeable loss of color saturation. <SIGH> again...and back to the drawing-board.
I'd been ignoring Photo Mechanic's "Save photos as..." feature for a long time -- until recently. Holy smokes, why hadn't I tried it before? It's just what I'd been looking for in a save-for-web application! Consistent with the rest of PM's features, this one has a very clean, straightforward UI. It enables you to select the quality setting for JPEGs; to assign the saved images to sRGB; to select 72 PPI output; to resize to user-selectable maximum pixel dimension for the long side of the image (retaining the original aspect ratio); to rename while saving, with PM's usual tons of choices via the variable feature; at your option, to retain EXIF and IPTC data in the output files. There are watermarking and sharpening options (the sharpening needs some improvement, IMO). As with other such applications, it enables you to save a 'recipe' for quick setup the next time you do a save-for-web operation. And, it does its saves gratifyingly fast -- no small feat on this older/slower machine I'm using. So far: no noticeable loss of color information during the saves.
Considering how many images I have to save for the web at times: I'd consider PM worth the asking-price for this feature alone!