Just want to throw in my input to this thread and to support Dano's Performance:
Dan tuned my ECU about a month ago. I live in Iowa at the moment but will soon be in Cali for the foreseeable future.
Engine wise, I have a K&N race air filter, pair valve deletes, and a straight through Akropovic slip-on. No cat.
Dan tuned my map to the requested Yoshi R77 slip on (map most close to the system I have) as requested.
I too, see a "night and day" difference as previously described. BUT...do let your bike do a TPS reset. I don't know if it actually matters, but i did my homework and just did it anyway. Like any Honda ever, start it, let the fan kick on (could be 15 minutes later) without touching anything, and then shut it down.
I honestly didn't notice much besides the noise on acceleration, but I have noticed better than normal slow-riding conditions. Deceleration fuel cuts are awesome. You loose the "jerk" when riding at constant speeds. If your bike is primarily a street bike or a to and from work bike, do it. It's worth it. Be real with yourself. The occasional track day doesn't mean that you'll suffer in this department.
My friend rides a BMW supersport. Though I didn't notice the acceleration mapping he said that he did as i was keeping pace just fine with his 1000.
Hope this helps! Thanks, Dan!