I think the gotchas aren't for the early adopters and power users. It's for the people who will eventually make up the larger, more lucrative percentage of their user base starting with the friends and family of early adopters who are recommended to it.
Once they're set up with it, the idea of "importing and exporting between dozens of password managers" is meaningless. And gotchas aren't always limitations but can be "positive" like well meaning features, integrations, your company using it (so you too), etc. Lock-in comes in many forms.
Out of curiosity, why so many rotations away (and back to) BW? Most people I know stick with a single password manager almost permanently, or at least unless their manager has some kind of earth-shattering vuln announced that just shakes their trust enough to move.
I'll pass it on to the team! The designers and product people put a ton of work into making both RB and Tunnelbear delightful, and I'm glad it's making a difference :)
Once they're set up with it, the idea of "importing and exporting between dozens of password managers" is meaningless. And gotchas aren't always limitations but can be "positive" like well meaning features, integrations, your company using it (so you too), etc. Lock-in comes in many forms.