AirVPN user here, switched after Mullvad discontinued port forwarding, and I really don’t see what issues they might have from a “technological point”? The only real issues I’ve had are the application’s slightly outdated UI, and the lack of application based split tunneling. Other than that, Air appears to have all the same features as Mullvad and even some they didn’t, like the more robust DNS filtering, and the ability to sort servers by latency and P2P download speeds.