I tried Aperture not long after it was released years ago. And LR a little later. For me, the non-starter for Aperture was how it handled "non-destructive" brush or gradient edits, such as dodging and burning. If memory serves, an intermediate hi-res tiff of the RAW file was created which you'd then dodge/burn with a brush. You could delete a particular brush edit but weren't able to later modify the strength of a particular brush attribute (exposure/contrast/sharpening/black level/highlights/etc, or its extent/positioning. That was just dumb. And that tiff associated with your RAW took a big chunk of memory.
In contrast, LR was a breath of fresh air. Any brush/gradient/clone operation and attribute could be *modified* (not simply deleted) at any time in the future. Overall it was a much smoother flow.
Also thinking about Apple's and Adobe's core business, it was clear to me that Adobe's being primarily about image science they were going to be in it for the long haul with frequent updates and interesting new features. Adobe also had a super strong presence in the commercial graphic design and publishing world. I also like how Adobe reached out to photographers for opinions/guidance and focus sessions. I don't know how they got my name, but they invited me up to their SF operation twice for a roundtable with a couple of other photographers kicking around ideas and opinions. And paid me a few hundred dollars for my time - a nice and unexpected surprise. Once a couple of Adobe LR employees came to my house to talk about LR what I liked and didn't like, and to see how I used it on my computer. For Aperture, it wasn't so clear what the future was, and felt if it didn't meet Apple's revenue projections/requirements, the app would be canned sometime in the future.
Though I held out for two years hating the idea of going with a LR subscription, I'm now glad I switched as LR just keeps getting better and better.