Extremely poor start - people have to sign in via Facebook or Twitter before they can even find out who/what you are.
Of course this is a side project, so user experience may not matter. But he asked specifically about experience, so...
We definitely don't want to trick a user into signing up - we want to be as clear as possible.
I dont mind giving feedback/review. I mind if apps spam my followers, to gain traction.
To be clear we are not spamming upon login though - so you're ok.
I'm not even sure what your product is - but I do get that it probably wants to have access to my data to do its business. Allowing you access to my posts, friends, etc, is fine, but I get suspicious when an app demands write-access without justifying it.
However I do agree it would be much better to set up user expectations for the benefit of linking their account: explain to me why you need this information in a simple, preferably visual way.
Also, would be great to have a way to unlink my Twitter/Facebook credential from the app.