I'm a bit of the KISS philosophy .. Keep It Simple & Stupid Lots of them all have these ricey displays and fancy "AI logic" which people tend to get sucked in by, but really they're probably a no better boost controller than some of the cheaper ones with a simpler display, but do what they are supposed to it.
A lot of the more expensive EBC's have all these fancy functions and learning modes, and like SK said, who knows what they're really doing. An EBC setup incorrectly can spike similarly, go infinite boost, or cause other problems.
Bleeder for cheap, EBC for later. None will kill your car if correctly setup.
ProfecB isn't even a bad choice with the KISS stuff at a good price - I've seen some big HP cars with them in Japan. Then again some reckon they can cause problems at higher levels, but you hear stories about every little performance part. Can pick them up for $300-600 from new to 2nd hand. Works fine in my car.. couple of knobs, high/lo selector, and sharpness (to adjust on different setups so boost doesn't drop at higher revs). Thats it. Does the trick. Newer one is a bit ricier with the LCD.