I've had Bigpipe for about 18 months now and have no complaints. The only issue I've had was about 3 days in and we lost all internet. I was travelling in Auckland at the time but logged the problem via my phone, had a IM conversation (from memory) and Chorus came the next day and sorted it - ended up being an installation error with connecting a wire somewhere.
Since then not a problem.......
Oh, and they upgraded me from 200/20 to 1000/200 earlier this year without me doing anything. I've measured 930Mbs down ;)