The phone, even with Blur, will look like it runs pretty smoothly. With the Blur removed, you notice a slightly faster snap to everything (panning through screens, opening apps, switching between apps, etc.). Beyond that, some people simply just care way too much about their Quadrant benchmark scores.. if you've ever overclocked your computer before, you'd quickly realize how little of weight the synthetic scores truly hold.
Personally, I like these ROMs simply because they remove things I don't need (bloatware, Blur, etc.) and add a few extra features that are useful.