I have been researching a braking system for my toad, and here is what I have found.
Essentially all states have a 3,000lb towing limit without requiring brakes, but a few states are 1,500lbs.
My vehicle is around 3,100lbs, so I suppose the laws apply to me. As safety and liability conscious I am, I am definitely going to use a braking system in my toad.
Also, I plan on traveling from Michigan to Florida (my youngest son lives there) with the RV, so I definitely want toad brakes going over those steep hills some call mountains. For that reason alone, I am going with a braking system.
While the laws in most states are written for trailers, and not specifically towed vehicles, the Federal DoT definition of a trailer includes a toad. As well, the scuttlebutt is some states have been re-writing the towing laws to specifically include toads.
Here is a brakedown on the laws by state. There is no reference on this page as to what the law document is, but further research would probably reveal such information:
Trailer brake requirements are also typically published in your owner's manual of the towing vehicle, and most of those are way under 3,000lbs. So at minimum, there could be a liability issue should you wipe out a family of kids on the highway if you were disregarding the owner's manual information whether or not you are complying with the state law or not. And of course, you don't want to do yourself in as well.
So I see it as a safety issue.
I am about to buy a brake system for my setup. So admittedly, my response comes from research on the topic and not actual use, so take my comments at that level.
For your other question, it is true the vacuum brake boost will not work when the engine is off. However, federal safety law requires the brakes to work manually without boost, and that the pressure applied is within the realm of the typical driver.
So I don't think the pressure required to apply the brakes without the vacuum boost is all that more than with it.
Also, most brake systems have an initiation sequence wherein it depresses the brake several times (while the engine is off). This is actually done to purge the vacuum from the system. This ensures that the application of the brakes are consistent with each depression of the brake system.
Some of the braking horror stories I have heard (brakes locking up, flat spotting tires, no brakes applied, etc), are at least explained away by the manufacturers in that the owner did not to the initiation cycle to purge the vacuum from the brake system.
To me, that sounds plausible, as I did observe in a couple of videos that the brake cylinder (from the brake system) changes the distance it travels each time it is operated when purging the system. That only means one thing to me - the vacuum is being purged from the system (unless the brakes are bad on the car).
I have looked at several of the different brake systems, and while I have not yet ordered one, I am getting close. I also talked to Blue Ox when I was at Hershey earlier this week.
The three systems I have been looking at are the Brake Buddy, Blue Ox Patriot, and the RViBrake2. I want a portable system rather than a built-in system.
All three systems depress a plunger into the brake pedal and use an accelerometer to determine when to depress the brake. They all claim to be proportional (that is, if you brake soft, the brake system brakes the toad softly... if you brake hard, the toad brakes hard).
Other - older system are not proportional, which means you have to set the brake pressure manually, which may be too much or not enough.
The RViBrake2 is designed by the same person that invented the Brake Buddy. He sold the company a few years and had to sign a non-compete agreement, which has since expired. So he designed the RViBrake system. Whether this is good or bad, I have no idea.
Both of these systems use hydraulics, and include a small pump in them. So there is a short delay between actuations wherein the hydraulic system has to be recovered.
The Patriot uses an electric cylinder, and while this means there is no recovery time, the response time of the cylinder is very slow in comparison to the hydraulic system.
The Patriot also has an internal backup battery, which means the brake will still work (at least for awhile) even if the vehicle battery is completely drained.
The RViBrake2 system proports to be able to use a battery for up to 3 days without fully discharging it... however, I am a bit skeptical about that (I guess you need to emphasize "up to"), and some owners have reported a full day's use.
Regardless, I bought a Stanley portable battery system (one of those McGuyver tools that has a jump start battery along with an air compressor, light, etc). I also plan on installing a battery charge system from the coach so that it can keep the battery topped off by the engine alternator.
At this point, I am leaning towards the RViBrake2. My wife likes that it is small and lightweight, as she may very well be the person removing it when we arrive at our destination. I don't care one way or the other, I just want the best.
I also like the idea that the RViBrake, since it is so flat, depresses against the seat frame/floor pan, which is different from the other systems that depress against the seat cushion. Since the cushions tend to depress when that happens, they might not brake as accurately.
I also like that the RViBrake has outstanding service, and when they recently updated the RViBrake to the RViBrake2, existing owners could upgrade for $100 plus their old unit. That says a lot to me.
Also I like that the RViBrake2 has an external antenna, which while it takes a few seconds to deploy, should ensure better communication with the remote in the coach.
Well, sorry for being so long winded about this, but now you know about everything I know about these systems. It is easy to get a lot of info these days from the internet (you tube, and other places), but the same old caveat applies - be a bit skeptical about what you hear, and you should be able to sift through the chaffe and come up with the answer.
For example, one criticism of the RVI system is after stopping at a rest stop mid day and starting the engine (which some tow vehicles require), the RVI system no longer works properly. However, RVI says you have to perform the initiation sequence every time you start the engine to bleed the vacuum again, and it seems highly likely to me that is not being done by some complaining about that issue.