How each app actually works
Both show you a stack of profiles and ask for a yes or no. Tinder then leaves the conversation open to either side with no deadline. Bumble puts the first message on one side in opposite-gender matches and expires matches nobody starts. Same format, very different inbox.
Scale against signal
Tinder will nearly always show you more people. Bumble will nearly always show you fewer dead matches. If your problem is having nobody to talk to, Tinder fixes it. If your problem is fifty matches and no conversations, Bumble fixes that instead.
Where your city decides for you
In a large city both are busy and this is preference. In smaller places Tinder's density usually wins on availability alone. Run both free for a week and count new profiles on day six before you spend anything.
What you get for paying
Tinder Gold changes how you spend swipes because you can see who already liked you. Bumble Premium is broader, with filters and travel mode. Neither will rescue weak photos, and both are cheaper per month on longer plans you may not want.
Safety and who you meet
Both offer photo verification, blocking and reporting, and neither runs background checks. Bumble's first-message rule cuts a lot of unwanted openers, which is the clearest practical difference. Keep the first date public either way.