I'm into 3D and AR development before it was cool and even did an ARToolkit port for Silverlight back in the days. Of course I also had to give ARCore a try.
The release of ARCore was nothing less than an answer to Apple's ARKit, although most of the ARCore algorithms originate from Google's Tango which is being worked on since years. Both provide a similar feature set with motion tracking, horizontal plane detection and ambient light estimation.
I don't own an Apple development environment so I can't compare it directly to ARKit but I tried out some of the experiments myself on a colleague's iPhone a few weeks ago. ARKit's tracking was really stable and I think ARCore is a bit behind but it's hard to say how it compares now without having my own side-by-side comparison. This video though seems to confirm this observation and it's not surprising considering Apple owns the whole stack and can calibrate their sensors and align the software much better. The next generation of their mobile devices will surely even more improve it and Apple can move a bit faster here but will users care about those slight tracking differences? I doubt it.
There's a great in-depth article comparing Apple's ARKit and Google's ARCore which also covers the tech under the hood: How is ARCore better than ARKit.
Wikitude and Vuforia are two larger third party libraries that provide SLAM-based marker-less tracking for many platforms since quite a while and much before ARKit / ARCore were out. I'm sure they will continue to innovate ahead but I fear both will be become less and less relevant since the licensing cost and third party SDK integration is always a big disadvantage. Even more important can Google and Apple really influence the hardware manufactures and improve the calibration to reduce the tracking errors to its minimum.
I'm a HoloLens developer since day one and actually already before it was publicly available, so I could compare it to Microsoft HoloLens but ARCore/ARKit play in a different league and actually complement each other.
The Microsoft HoloLens is a revolutionary device that might be a bit ahead of its time. The HoloLens shows us how mobile devices will work in the future. The inside-out tracking running on a custom chip is still leading and unseen in any other untethered, mobile device and the NUI input is top notch with voice and gesture input. The stereoscopic 3D see-through displays of an HMD provide a much more immersive UX seeing the world around you with your own eyes than holding up your phone/tablet in an unnatural way to see the world though a monoscopic 2D camera lens on a mobile phone screen.
ARCore/ARKit are taking a different approach and bring AR to the masses on existing hardware and there's a place for all 3. I can easily imagine building cross-platform solutions which target high-end experiences with the HoloLens for a smaller enterprise audience and a counterpart app with Google ARCore / Apple ARKit for the masses. Another benefit of classic mobile AR like ARCore/ARKit is the outdoor support and having easy access to GPS location data which I leveraged in this demo.
The news about HoloLens v2 with the new HPU / AI chip are exciting as it will open amazing use cases. Microsoft is definitely leading the industry with innovation in the AR/MR space and no competitor comes close to its bleeding edge technology. HMDs like the HoloLens are the future of mobile AR/MR but until HMDs will be become cheaper and in forms factors everyone can enjoy, ARCore and ARKit are great additions to the AR/MR landscape providing AR on current gen mobile hardware driving mass adoption and helping to mature the product design challenges.
It's a great time to be a 3D developer!
Below a few more GIFs from my experiments. See all in full length at my YouTube channel.