Acer Aspire 5740g vs Dell Studio 1558

[JustJohnny]

Hello, i want to buy new laptop and i'm wondering between these two models, i'm building a gaming pc right now so it wont be primary for games (well i still want to play something on it when i'm not at home) i will use it mainly for university - writing lectures, programing, using programs like AutoCad and SolidWorks, web browsing, watching videos and so. The Acer is cheaper (about 90$ i think) with better specs but i've heard that they are build cheap and dell are build a lot better and dell has 3 years warranty vs 1 for the acer, also whats the battery life on both? longer is better as i'm going to use it mainly at university, so tell me what you think, thank you.
Here are the specs:

Acer Aspire 5740g
processor: intel core i5-430m (2.26GHz, 3M cache)
RAM: 4GB (2 x 2024MB) DDR3 1066MHz
HDD: 640GB SATA 5,400 rpm
video card: ATI Mobility Radeon DDR3 HD5650 1GB
display: 15.6 inch WXGA (1366 x 768) HD Ready

Dell Studio 1558
processor: intel core i3-350m (2.26GHz, 3M cache)
RAM: 4GB (2 x 2024MB) DDR3 1333MHz
HDD: 500GB SATA 5,400 rpm
video card: ATI Mobility Radeon DDR3 HD 4570 512MB
display: 15.6 inch WXGA (1366 x 768) HD Ready