Well, it seems like there is a great debate about windows rotting. I can attest to the fact that it happens, but it isn't always the brand.
Properly flashing and caulking/sealing a window is probably the biggest reason for premature failure of a window.
While it is possible for a wood window to rot in 4 years, it isn't likely if the installation was done well, and the windows were painted with a quality exterior paint over a good quality primer in a timely fashion after install, among a few.
Any window, even the best vinyl clad product can have problems if not install properly. For example, if you have wood siding and wood windows, and there is no head flashing, this is a great opportunity for a start of a problem.
The size of overhang on the structure also lends itself as a cause for premature failure. If the window is always getting rained on, it will fail sooner. Excessive exposure to sunlight and heat will also drive failure.
Consider everything, window design, building design, proper installation, proper painting, etc., when you evaluate a windows performance.