I am not in the market for a city car but the Skoda appears better. I would not want to do 15 miles a day in one in the country though. As they are highly recommended for city use, your daily mileage seems high. A Golf is the best car and will probably have better residuals too. Good cars don't have that much wrong with them if your mileage is low so I would not bother about the warranty. What Car on line test of the cars is the best guide and gives you a breakdown of the best engines to get. I mean a secondhand Golf of course. At least that is a pleasure to drive all the time, wherever you drive it.
Give it a test drive at least. I really chucked my toys out of the pram when I had to trade my beloved Skoda in for a new Kia Carens because I really didn't want one (no choice really, the Skoda wasn't big enough for us any more), but it's actually really growing on me. And Kias have a lot of the good stuff as standard, even on the basic model.
I was also going to mention Kia, as they are owned by Hyundai and the platforms are shared among models. The Kia Picanto is the same as the i10, except you get the 7 year warranty.
As TobyLerone said, a longer warranty isn't guaranteed to put you in a better position - if the car keeps going wrong, sure you get it repaired for free, but you have constant inconvenience taking it and picking it up from the dealer, sorting out alternative transport (although courtesy cars should be available, again not guaranteed); even if the Skoda only had a 1 year warranty, if it never goes wrong you're in a better position than with a faulty car covered for 5 or 7 years.
Obviously these examples are best/worst case scenarios to illustrate a point; all cars have the potential to be unreliable.
I would say have a test drive of both cars and see what you feel most comfortable in.
I love Skodas, so I'd go with that. A long warranty does not outweigh better reviews IMO.
Have you thought about a Kia? They do a small one (can't remember what it's called) and they do a 7 year warranty. We've just bought a new 7 seater Kia and I'm really growing to like it. They have honest customer reviews on their website.
We have a family car and now need a 2nd car for schoolpick ups (will do about 15 miels a day) Huyndai have 5 years warranty buy my husband prefers as it is a car that has got good reviews. My argument is that Huyndai has 5 years warranty so even if citigo has got better reviews, we have 5 years warranty with huyndai if something goes wrong. also, if I buy 2nd hand ( 1 year old) huyndai i will pay 6000 and still have 4 years warranty. what woudl you do please?