Well... Im an engineering student and I have a $2500 18.4" HP laptop.
I bought it to run the high output demanding CAD programs, and multitasking with multiple documents open on the screen at the same time (and for some gaming ). I dont have much issues carrying it around but then again im kinda a strong kid (All Conference lacrosse defender in high school) but if they arent in a engineering field or something similar, its not worth it.
I would stay away from ACER as well. Unless you bought it from best buy or another retailer with their own warranty. and do not buy a mac, you are wasting your money on all show and no go.
As far as specs go, a 15" screen seems like the best all around choice between portability and function. Ive tried using a friends 10"er and i found it really irritating to type and view the screen.
For a laptop of this size and decent hardware, i wouldnt spend a dollar more than $1000