There isn’t much difference between the mainstream (VW, Audi, SEAT, Skoda) cars in VAG range. The A3 and SEAT Leon (Also Golf and Octavia) are very similar in terms of mechanical and electrical components with just a few subtleties to sway individual taste. Quite a few reviews put them on an a par (https://www.leasefetcher.co.uk/versus/seat-leon-vs-audi-a3). However, it all seems academic as most have disappeared off the scheme or require substantial Advance payments