It will cost an extra $30.00 a month to upgrade from my existing 30/10 to the 200/20 which doesn't sound too bad but I was already paying $95.00 a month for the 30/10 plan taking the new cost to $125.00.
The sweeteners offered like sky upgrades, mobile plans etc are not really of interest to me.
So quite a similar dilemma to mine; good news re Big Pipe probably arriving at your door, so going with them would save you about $20 a month (if you take VOIP through 2Talk) or $26 (if no VOIP needed). Similarly, I'll save $30 a month going to 100/20 with Big Pipe compared to what I'd need to pay if I upgraded on 2Degrees.
This is the reason I've taken the advice to avoid contracts if feasible - allows one to take the best offer at the time, rather than being tied to one company at a set rate for that period.