While biphasical clearly increases continuity and the length of days, it isn't overall nowhere near as strong feeling that you get with Uberman.
When it comes to my nap, I had a great one. I slept the whole time and woke up relatively effortlessly. My core sleep wasn't that good - I was tormented by mosquitos and therefore woke up constantly. It was amazing how many times I woke up considering I just slept four hours. Despite this, I had no problems staying awake during the day. This is going really well so far.