One of our cars is a MPS 6 (2006). My dad has mainly been using it for business trips up and down the country. The reason he bought a 6 is because his mate own's one, and when my dad drove it, he liked it. The performance is'nt that fast (0-60 in 6.6, top speed is about 150mph) but its enough for a car that is going to be on a motorway its whole life. The space is alright, but you feel a little...cramped in the rear, and the long boot is big, but very awqward to get things like shelfs into. The end of the rear windscreen hangs out alot.
It has now done 37,800 miles, and has never missed a beat. The only major problem we had with it (which we still never discovered why it happened) was that one time about 8 months ago, me and my dad were running down the motorway at about 4 am doing about 135-140mph. For some reason, 3 of the bolts in the rear left wheel decided to shear off and they came off completely. We pulled over, and had a look at the damage. It wrecked the alloy wheel (hub was destroying) and the brake pad was shattered, and the hub was bent. Probably due to the wheel smacking it at 130mph+.
Either way, apart from that one problem, its been a good car.