Can't you? I did. I went with the cheaper alternative and I'm more than happy with my decision. Macs are nice, but they're not a necessity.
My MBP is 4 years old and still hasn't slowed down at all, even when I started maxing out the processors and RAM for hours on end by producing music. It was pretty expensive at $2000, but IMO the longevity makes it well worth it, and of course it's still probably going to last at least another 5 years at least.
