Yeah, it's significantly faster.
Is it worth the upgrade? What are you doing? The more disk based processing being performed, the more benefit you will see from an SSD VPS.
I got a killer deal on my VPS from Servermania. I only pay $56/year for mine. Woo!! It's unmanaged, but that's no big deal, just do some reading, throw WHM and a good firewall on it. Takes a couple hours to configure properly.
Its STUPID fast.