btdig seems better as it doesn't have annoying pop ups, which are constantly brought up on btdb, even with ublock origin and noscript. I would not be surprised that btdb is buying ads from an ad provider that sell js injections to a MPAA operated third party.
btdb is nice because you can sort by seeds, you cannot with btdig.
To be honest I stopped using classic torrent indexers entirely since I started using DHT indexes. They have much larger choice. The issue is that you cannot "post" magnets links on the DHT automatically (I think you cannot), so the DHT works as long as people are finding magnets or torrents elsewhere. It's bringing more decentralization, which mean more chaos but much less traceability.
It did not work terribly well for other networks like Gnutella; it just gets flooded with spam and malware attacks. Good engineers and researchers never had the chance to develop solutions to that problem because the copyright industry delegitimized peer-to-peer and pushed everyone to more centralized systems (by abusing the court system).
I mean, this is known point of vulnerability.
Maybe it's because owners of popular bittorrent software don't want that feature?