Twitter's mobile web site is the most unreliable site I encounter with any frequency. Fully 80% of the links I get to Twitter fail to load, telling me to try again, which only works when I fully refresh the page.

I don't know how it compares to their native app.

Done in-house, I'd bet, and that's another disconnect to overcome.

Outsourcing website and/or mobile dev to external company, the focus is often more going to be on whizbangflashy, vs sleek/slim/fast/simple, to justify whatever budget they're getting.

I do find that I end up using the mobile web client for twitter as often as i do the native client. It's not much in either case, but the mobile web client is generally 'good enough' such that if that's where I land, I don't feel a need to jump to the native client.