I was intending to go with Nistune on a >300rwkw 26/30 but figured that after $450 for the ecu, $700 on two Z32s and $650 on a good ebc I was over the cost of the Vipec board + mac valve. Even with one Z32 it's close in cost. I don't have to worry about AFMs, and also get overboost protection and some other features.
It was the $ and overboost protection that made my mind up. And if your tuner likes Vipec it's also a plus to stick with that, although for a 5 hour trip to Sydney I'd say (having had 2 Vipec tunes, one of which was by a proclaimed Vipec specialist, but neither of which was very good) go to Hitman in Penrith, leave it for 2-3 days, pay your $1250 and come away with a great tune - power and driveability - as well as emissions certification.
Just my 2c.