We, as Mac users, are spoiled with the wealth of raw converters. It sounds like the need to have a DAM, and particularly one that is integrated into the raw converter, is the constraint in this tale of woe.
I do not use a DAM and do not keyword or label everything I shoot. However, there are perfectly viable alternatives to Lightroom that will do all of this. Photo Mechanic is an example. Once you uncouple the DAM from your raw converter, you can experiment with applications that focus on raw conversions to find which one(s) is(are) the best for your needs.
In addition to LR and CaptureOne, these come to mind, in no particular order:
Iridient Developer (download the current beta - it is very nice)
Raw Photo Processor
Raw Therapee
DXO
Fast Raw Viewer is an incredibly powerful tool for viewing and culling raw image files and integrates nicely with raw converters, especially LR/ACR (it will write compatible XML files) and RPP (it will write RPPS files). You can assess the raw file in real-time, not a preview or a full-rendering that takes time to produce.
In other words, you have options. Unfortunately, some Aperture users have workflows built around Aperture and need backward compatibility or something that will assimilate Aperture libraries and metadata, etc. If that is the case, then LR and C1 are the only two solutions that seem to be attempting to accommodate Aperture users in this regard.
They all have learning curves and advantages/disadvantages. If you simply refuse to adopt LR, then these alternatives are worth a look. I, personally, do not use LR very often - not out of spite, but mostly because I do not need most what the application offers and find that its raw conversion is average at best compared to other converters.
Aperture also still works, but I understand the desire to start planning for obsolescence.
kirk