Owned since 15,000 miles, and have now driven it a further 130,000 miles. Engine is fantastic, the best thing about the car. Still no oil leaks, even after all those miles.
At 70,000 miles, a small hole appeared in the exhaust just behind the CAT, and no compatible third party exhaust could be found that fitted, so a SEAT original had to be fitted: Cost, £600. To fix a hole!
At 100,000 miles, steering column switch cluster started to fall apart and short internally, damaging the indicator/flasher unit in the process. SEAT UK/Europe replaced the switches easily, but could not find a simple flasher unit anywhere in any warehouse for a month, and in the end I had to go to a scrapyard to find one myself and present it to the garage so I could get my car back.
At 120,000 miles, synchromesh on the gearbox started to fail, making it impossible to change from 5th to 4th. Fixed by gearbox specialist, cost about £600.
At 130,000 miles, the driveshafts both had to be replaced due to severe wear - one actually snapped.
145,000 miles (just now) - Oil warning lamp suddenly came on, stopped, found plenty of oil. Car then ran OK again. Chief suspect is oil pressure sensor, not yet confirmed.
Light silver grey seats are terrible for attracting and keeping hold of dirt - I eventually gave up trying to keep them clean, and just fitted seat covers over my filthy seats.
The car has always been ludicrously fast for a small diesel, and yet incredibly economical, with emissions low enough to put it in the £30 per year tax bracket.
Handling (on my diesel model at least) is relatively poor; the heavy engine block tends to want to keep going in whatever direction it's already going. However, I originally bought the car as a fast long distance motorway cruiser, and for this it is excellent, humming along effortlessly at very high motorway speeds for mile after mile.
The oil specified for this engine (VW spec 505.01) is unusual, expensive and rarely available in garage shops, but the owners manual states that failure to use the right oil can result in serious engine damage, so be prepared to keep the right type of oil to hand and never be tempted to use 'ordinary' oil.
The front light clusters are stupidly hard to get at from behind, due to the very close proximity of other components in the engine compartment - sidelights in particular are ridiculously hard to change, and I suggest replacing both with LED bulbs the first time you have to change one, so you'll never have to do it again.
If you like carrying out your own moderate to complex repairs, be aware that there is not and never will be a Haynes manual available for the Arosa - not enough were ever sold. This has been a problem enough times for me now that I would not buy another Arosa, even though I love the car.