Meh, it's just a solenoid (or pair of solenoids in some applications) with a momentary switch and basic DC electrical components. Get whichever one is made by a reputable company for a reasonable price and you will be fine. Some are made for specific applications with pre-bent and flared brake lines which save time and effort from those that don't want to deal with doing their own lines. But really it is extremely simple to do your own lines so unless you really hate doing that then I say save a little money and enjoy making your own. I wouldn't overthink it too much being that it is a relatively simple system. Just remember that Captain Obvious says to "Always bleed your brakes afterwards!" lol