We use pkarr at iroh.computer for node discovery. It is anything but slow. It is very rare for a lookup to take more than a few milliseconds. It is sometimes faster than our non-p2p node discovery option which is using DNS.
DHTs get a bad rap because of many recent DHTs that were horribly inefficient. But mainline is different. Many of the design decisions of mainline seem very limiting at first, but make a lot of sense for perf.
E.g. a pkarr record can only be 1000 bytes, so the entire message fits into a single non-fragmented UDP packet.
Creator here. It takes around 30ms to resolve a public key DNS entry on the DHT. After the first resolution, the entry is obviously cached according to the configured time-to-live (ttl).
It's not as fast as regular DNS, 30ms is still very quick.
This is their example:
http://7fmjpcuuzf54hw18bsgi3zihzyh4awseeuq5tmojefaezjbd64cy/