Hydraulic disc brake systems - Which to buy?

[Loren B.]

I need help in deciding which hydraulic disc brake power unit to install on the trailer. I have a BrakeSmart brake controller (excellent unit) on the pickup.
　
There seem to be two different styles. The more common system uses an electric pump mounted on the trailer to supply hydraulic pressure to the brakes. From what I have read, it seems these pumps do not run until the TV signals for brake application. At that time, the pump starts and as pressure builds it is routed to the disc calipers. I have not heard of any of these systems that incorporate an accumulator.
　
The inherent design flaw with this type of system is the delay from the time braking is demanded and the time that pressure builds sufficiently to apply the brakes. I expect that this delay is different for different systems.
　
The other style system uses a standard brake master cylinder to apply the trailer brakes. The piston is moved by an electric servo motor and gears. This system would also have some delay as the rod is moved into the master cylinder, but presumably the delay is less than with an electric pump.
　
It appears that the master cylinder system is made only by TowBrake. See here:
Welcome to Towbrake.com
　
Besides the (presumably) shorter time delay, the advantage to the TowBrake system is that it has provisions for a parking brake. After talking to the company, I learned that the parking brake isn’t useful for long-term (over an hour or so) parking, but can be used as an aid to loading a utility trailer or hitching up.
　
Does anyone have any experience with either of these systems? I would appreciate your opinions.

Thanks,
– Loren