Since I shoot in an urban area, most of my OOC images exhibit keystoning, some very severely. This has meant that, except for the obvious clunkers or keepers, I have had to go through the images one by one after import and do a quick and dirty manual keystoning adjustment in order to be able to get a sense of whether a particular image is worth pursuing further.
Last night I installed LR5 and tried including the Vertical upright tool in my import preset, and it works like a charm, all the images automatically get a keystoning fix and crop to bounds that makes the initial review process a LOT faster. The tool does not work perfectly, and in fact, none of the images are corrected properly -- on any image I was going to print I would remove the auto adjustment and do a from scratch manual correction -- but it is certainly good enough for initial review. That alone makes the upgrade a crazy bargain for me.
Final verdict - tool does not work accurately enough for "destined for the wall" corrections, but is close enough to really streamline initial image reivew.