I have the Barney - it's a great cage. It's true the plastic base isn't as tough and solid as the Savic ones but it's absolutely fine. Costs about £54 on Zooplus - it's a great size cage for a Syrian and comes with a good house and shelf so not much more to buy.
Alternatively there is the Savic Hamster Plaza which has a big front opening door - sold by Pets at Home - it's 100cm x 50cm. It's normally £75 but I saw them selling it for £56 online the other day.
The Prevue is probably not as well made and dimensions aren't as good.
The Alexander on Zooplus is also a brilliant cage. The Barney and Alexander also have 7mm narrow bar spacing so could be used for a dwarf hamster in the future - with the right set up.
https://www.zooplus.co.uk/shop/small.../hamster_cages
http://www.petsathome.com/shop/en/pe...r-and-rat-cage