Hmm, i'm really not a jet guy, never used an edf either but i would immagine their would be benefits to turning the brake off in that kind of application.

What leads me to think that is brakes are normally used for 2 reasons; Mostly to allow folding props to collapse, without the brake they might keep turning and reduce glide time. Then parkflyers sometimes like to use the soft brake to help slow down for landing in confined spaces, some planes react negatively to braking the prop though. The longer the prop the greater the influence brakes have on slowing down the plane, a long prop on a short wingspan may cause the plane to roll rather annoyingly when the brake kicks in.

On a loaded jet i certainly wouldn't want to slow down, and to brake a small turbine even to a complete stop shouldn't really increase drag that much compared to doing the same with an 11x4.7 slowfly prop for example. The surface providing drag is far greater and the edf impeller offer much less surface area, needing high rpm's to move a lot of air...

I would definitely keep it off in hopes of getting slightly longer flights and better throttle response when allready cruising.

Correct me if i'm wrong all you edf gurus out there!