I know you already have a GPS for your Brittany but if you are looking for an e-collar I would suggest getting one with a beeper. A lot quicker to locate a dog on point than the GPS. There is a guy (fourtrax) on this site that runs a DT Systems 2430 on this French Brittanies along with a GPS. He likes the DT collar and has had no problems with it.
I've run TriTronics and Dogtra on my Brittanys but never had a beeper. I will not go through another season without a beeper collar. It's frustrating not being able to locate the dog when it's on point over a big rooster.