My plane came with a Brittain B5C, but it wouldn't hold altitude or course worth a damn. Fortunately, we have one of the few qualified Brittain repair shops near here, but it took the several tries to get it right. The problem was that it had multiple problems so when they fixed one thing, the symptoms changed and they had to fix another. All told, I spent around $4k getting it fixed, but it now flies very well.It may take a few seconds longer than a new digital system to make corrections, but it is solid and cost a lot less that the newer system I was about to replace it with.