You're right about Acer's having mixed reviews about reliability. But we know more about past years models than current year models. Generally, laptops in the same price range will have pretty close reliability over time when they have the same general parts installed.
You'd want to look at a specific model rather than the entire brand. All brands have put out 'stinkers' when it comes to features, price and reliability. Acer always owns eMachines and PackardBell.
Some good options for what you need:Lenovo G560 £300 Lenovo G560 reviewLenovo G570 £350 Lenovo G570 reviewHP Pavilion G6 £366 HP Pavilion g6 reviewLenovo IdeaPad Z570 £450 Lenovo IdeaPad Z570 reviewLenovo IdeaPad Z370 £450
13" home entertainment laptopHP ProBook 4530s £450 HP ProBook 4530s review
a 'business class' laptop. The business class models are generally considered a bit more rugged and reliable.