I had a 60 plate that drank oil at around 1 litre per week, after numerous fixes and other problems VW booked it in for a new engine, however there was issues with the exhaust and gearbox so they bought it back off me and gave me a 63 plate GTI with 7k on. This one drinks around a litre every 1.5-2k miles depending on how you drive it, but from what I've read pretty much all TSI engines use a lot of oil, the newer engine however is significantly better than the old one as is the gearbox in my newer one.
The only issues I've had with the newer one is a HPFP (High Pressure Fuel Pump) failure so VW replaced the whole fuel system in mine, not a common issue from what I've seen so the newer ones are pretty reliable!
I haven't driven a corsa but I have been in one a few times and I think the Polo is a much nicer place to be in terms of comfort and quality.
Mine is due to be getting a stage 1 remap eventually, but at the moment it just has an induction kit and always run on V-Power + and it absolutely flies.
Also Shadow Blue ftw
![Cool 8)](./images/smilies/icon_cool.gif)