If I'm on my home network the latency is impossible to notice, I might as well be at my Mac. Same goes for bash completion, it works flawlessly. Once I'm off my home network it's a slightly different story, it just depends on the internet connection wherever I happen to be connecting from. For example I stayed at a hotel in Fargo, ND a few weeks ago and the latency was fine for the most part, but there were moments where the typing or completion would lag behind by a second or two and then catch up. Almost like lag in a video game.

Blink has mosh in addition to ssh, which if I understand correctly is much better suited to handling higher latency connections like that. I just haven't taken the time to set it up at home, so I can't really say how it performs.

All in all, if you're curious about using the iPad for this kind of thing I really recommend it. I absolutely love mine. Apple is pretty generous with their return policy too, I've returned a handful of their laptops just because I had buyer's remorse!