I have over the last two months had an incident with my brakes going to the floor 3 times. I have put about 4,000 miles on it during this time. My commute to work is 35 miles one way and pretty much 55mph with only about 7 or 8 times to stop, the rest is wide open door to door. Coming home twice the brake has stopped me at a light jsut fine (after about 30 miles of driving) but then after the stop, gone to mush and slowly to the floor starting my vehicle rolling. I started to order a brake master cylinder initally, but it didn't do it again for like 5 weeks. Is this just the sign of a failing master cylinder.....

PS had a front brake job but the problem was happening prior to that. brake fluid level is good.

any thoughts?

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85 300CD Turbo "Das Polluter" 230K sold for $3,000

98 BMW 323is

Symptoms are consistent with a faulty master cylinder. I would park the car until the problem is resolved.

Too dangerous to continue on this way. A master cylinder and changing all the brake fluid will probably get rid of the problem. Even if it does not you are being proactive in starting to run the problem down.
Otherwise you may land up with no brakes when you need them one day. Really not something to fool around with. You actually should have attacked the problem the first time it occured. Much like russian roulette now. Remember you basically just touch another fairly new car and it becomes a write off or you hurt someone.
Much cheaper to just fix the brakes now. I will never forget going down a long hill with no brakes working in my youth. There was a stoplight at the bottom with lots of traffic. Once was more than enough for me.