I haven't found it too annoying in my 35i. It is certainly noticeable when the engine turns back on...even causing the car to shimmy a little bit. I haven't had any issue with the delay not allowing me to accelerate as quickly as I'd like from a stop.
One thing though. Is it designed to activate the engine after 15 seconds or so regardless of lifting off of the brake or moving the steering wheel? I feel like it shuts the engine down, but then if I do nothing it turns back on on its own after 10-15 seconds.