My Himmy had about 4000 miles on it when I fitted it. The bike had certainly loosened up, but that only took 1500 miles or so.
As the dyno chart TEC use shows, there's more power everywhere, but it feels especially lively in the 4-6000 rpm area. Pulls much more strongly at 50+mph in top gear.
Feels more spritely at lower speeds, while feeling less asthmatic at higher rpm.
It's not a huge increase, but noticeable, so much so that fitted a bigger gearbox sprocket, which it pulls comfortably.
The net result is I have a bike which holds cruising speeds at lower rpm, with more power in reserve for overtaking. I can cruise at 70mph, while still being outside the nasty buzzy range of the engine. 60 mph cruising is much more relaxed.
If you wanted to maximise the pull of the new cam, you would keep the original gearing of course.