I'll agree with many here--- need isn't the right word. Want/desire is. I finally found my Feather Weight and I do love how it sews. I took it to a workshop right off, and the 8 lbs. is a plus. It also gave me more room in my rolling case for the supplies I needed for the class, so I only needed the one bag! Even my 301 would take up more room and I'd need another bag. But for piecing or any other straight stitching, 301 and FW's are worth it. My 15-91 is great too, along with the 66's I have, but they are too heavy.
So if you want one-- go for it.