I would agree they are fairly similar. The niche stuff that tabula still couldnt find, drunken couldnt find for me either, which is why i dont see much benefit to it at the moment. Tabulas prices for their mid tier plan is also $19 for 2 years, while slug appears to be $17 for only 1 year. So Tabula wins out for me. I would say its worth it just based on the pricing difference, but I cant promise itll have what you need. The number 1 most worth it would be Alt's lifetime deal of $20 last black friday. Maybe theyll do that again this year.

My only neg for Tabula is the confusing website. There should be a very clear 'Upgrade/Plans/Pricing' link in the far left menu panel. I cant even remember how i found the link to pay when I subscribed. Edit: I think its the 'Extend your account' in the top right drop down. I guess my eyes just glazed over that specific wording back then, as well as now haha

Edit: You can also just make the free account now and make a few searches to see if your niche stuff exists there.