yup, as in "harsh" some controllers boost drops off slightly, right near the redline, where'as this doesnt, which can be seen either as a good thing, or a bad thing, means you will be pushing the turbo all the way, but also means you will get the most out of it.
the idea of a electronic boost controller, is to give you greater control over boost.
how it behaves, ideally you want it in as soon as possible but depending how much gain you use you will lose a few psi topend.
offset on hks boost controllers works with a similar principle as gain, if you try really hard to get the boost in as early as possible, you will loose a tad topend, this trade off should be matched to the engine and turbo, for example a ct9 really doesnt gain much from a ebc, as it boost really early and naturely tails off up top, best you'll manage is a wee tad topend.
with uprated cams you will want less gain with a ct9 to help with boost up top now that the engine is enjoying(making power) right up to the redline.
imo
Phil