I had a ride on a fixie Mango at the Excel Bike Show - weird experience. It felt normal until I got to the first corner and tried to slow down. I enjoyed it though, so plan to switch the wheel round on this one soon for a fixie summer.
I took it out for a ride today. Nearly wiped out by a 4x4 driver who pulled out in front of me only to slam his brakes on as he hadn't spotted the parked car in his lane.

I only managed to avoid hitting him as I was looking ahead and saw it unfolding in good time. We exchanged 'pleasantries'. His explanation: "I'm in front of you - look I'm in front of you now". "Yes," I replied, "because you pulled out in front of me. Didn't you see me?". "Yes," he replied, "I saw you, but I was in front". When I pointed out vehicles at a give way line have to give way to traffic on the main road, he said "I haven't got f***ing time for this" and roared off at high speed through the 30 mph limit. Nice man.
Anyway - back to the bike. It was lovely to ride: smooth, quiet and comfortable. The brakes aren't up to much, but I guess I'm comparing them with my Bianchi. Got some admiring glances too, which is always a bonus!

I need to put some straps on the pedals as not used to riding just on flats - will be more important when 'fixed', I think.
Anyway, all good so far. Got it for just over half new price as well - bargain!