I have a mk4 and have fallen in love in a matter of weeks. Don't let some of the worst case scenario stories put you off too much. Some of it is outdated information. Replacement HiD bulbs can be had for under £30 now, I even bought an entire headlight to replace a cracked one, HiD Mk4 unit, £40 delivered.
Mine has 210k miles on the clock, still drives great, out handled a Leon on dual carriageway islands last night, not using the power, just taking the outside line smoothly while he tried to cut up on the inside line, squealing and understeering. Two roundabouts close together, not speeding at all, I came out of the second 8 lengths ahead, he pulled in well behind me and dropped to the legal limit after that. The lads from the club took a look over her last night too, we tried the pound coin balanced on the engine trick, it didnt move at all, even at 4000rpm, took two short sharp rev's to 3k to make it roll off.
The engine is so quiet and refined that you have to lift the bonnet to hear it running. The last MOT emmisions results were so good they beat our 25k mile Rover 25 1.4 all were under 10% of acceptable level, mixture was 0.999 with a target of 1.000
You could say I am rather impressed by these cars.