I've never owned an Asus so can't speak specifically about them. They may be well built by PC standards but the stiffness and strength is not going to be anywhere near a Macbook or Macbook pro (even if Asus did make components for Apple).
The Apple unibody design has a huge effect on the stiffness and strength of the casing. Even if Asus made their cases out of the exact same material and of the exact same thickness as the Apple it wouldn't be near as stiff. The unibody design results in a complete change in the restraint/boundary conditions (Engineer talk) of the component. The curved up bottom running effectively clamps the edges of the bottom of the shell and this by itself will make the bottom of the case 4-5 times stiffer depending on how force is applied to it. It will also decrease the stress in the shell by the same amount. That simple change makes a huge difference to the integrity of the computer. The top layer (with the keyboard, not talking about the screen) is also part of the same component as the sidewalls and bottom. This means the top is effectively clamped too and is thus also much stiffer. It also turns the whole thing into a sort of I-beam/sandwich structure type thing. This will also massively increase the stiffness and strength of the shell. Even the design of the keyboard are (which is recessed) has been considered to improve the integrity of the casing. As a result the components inside will experience less laoding due to bumps impacts etc... which is probably part of the reason that macbooks are quite reliable as their internal components don't suffer the forces that a regular computer's components does.
The only thing I've come across which is as good or better than a Macbook Pro is an IBM or a Macbook Air. I have an old pre-lenovo IBM and its shell is also a continuous piece and it made of a magnesium and its pretty bomber. But nothing is as stiff as a Macbook Air. They clearly let the mechanical Engineers have a big say in the design as I can't really think of any changes to the design that would keep it small but allow it to fit all the components. To get an idea of how big a deal the Macbook Air being stiff er than a MAcbook pro is consider this: if you increase the thickness of a beam or a panel then its rigidty increseas by the same amount cubed. I.e. double the thickness and 8 times the stiffness.
If Lenovo still make unibody designs then check them out. There's a reason why the were so ubiquitous among among the finance community. Also, i got my IBM for a great deal by getting a refurbed one.
In addition check to see if your University has specific agreements with any companies. At my Uni we get a 15% discount on any macs and a free upgrade to the three year warranty which is twice the regular student discount and they don't get the warranty upgrade. If there is a discount then there'll be a hidden website for your Uni which will not show up unless you're on a computer with an IP address registered to your College.
