Hey Android developer here. I used to have the same issue - even on a fantastic machine the emulator would run very slowly, or not at all. This is now completely different

You no longer have to emulate ARM. You can run the native x86 image, using GPU acceleration, and the thing screams. I can get multiple high resolution emulators running in parallel without issue. I'm still used to debugging every single compile on an actual device having been through years of slow emulation, but let me tell you that the environment is quite different now. Genymotion is even better, but not by much with regards to performance.