Everywhere is just like everywhere else. Soon everywhere will be called 'The Mall', you'll have to go online to check where you live. Like most tourists I had to rely on public transport/ taxis so info on how to reach the Akropolis by bus should be easier to find (53 or 062 from the Bus Station, next to the Railway Station). I would say it compares favorably to Malls in the UK. I've been to Meadowhall (139,355m²) a few times. Meadowhall has 12,000 parking spaces so the 3,200 at the Akropolis may soon prove to be inadequate as you really need a car to visit. Meadowhall Interchange (bus, train and tram) is a couple of minutes away, it's also just a few minutes away from the M1; but it is the only UK Mall with these transport links (apart from the tram network, these links were already in place). Sheffield and Vilnius both have populations of about 550,000 and local catchment areas of around 800,000 to about one million so apart from the recession, with good management both should have a bright future.
biggest shoppin center in eastern europe is in poland but i'm looking forward to see akropolis, afterwards i will be able to do small comparison :-D