Some differences we're doing from your situation:
We use Cucumber to cover the whole web app(but not flash or video processing), and only have some small rspec model specs on important methods involving billing.
Cucumber coverage is also very powerful per line of test code. We have 1000 lines of cucumber covering 5000 lines of code.
We aren't covering everything by tests. For example, I would have given up on the Facebook login test coverage, and just written some tests that mock a facebook-logged in user but not covered the actual login funtionality itself.
If we were not doing BDD, my time estimates for each ticket would have to double because the hair-pulling debugging time would skyrocket and kill productivity.
I would also hate working on a team that didn't have test-coverage because developer B might build something I don't understand or know about but I inadvertently break it and we find out 4 days later.
Another benefit: we can ruthlessly refactor and tear out code because the tests immediately identify if something broke.
There's also more payoff for your tests over time. The longer your project lasts, the more those tests pay dividends. Even they seem painful now, they are an investment towards maintainable code in the future.
My advice: keep going with TDD/BDD and consider Cucumber for everything but your most important business-logic methods.