Our first Prius was a used 2006 that we eventually trade in for a 2010 Prius 3. After a lot of back trouble it was getting hard to get in the Prius so we got a 2013 Honda CRV. Monday the Honda has to go as we got a 2014 Barcelona Red Prius v 2. So good to be back where we belong.
I was buying small suvs for years to get the high roofline and more upright seating which was needed for the wife with spine problems (stenosis). The Prius v does it all for us. It's nice to have all the benefits of a small suv and get over 40 mpg consistently. The best I ever got with the suvs was 24 mpg in the same conditions. That 32+ highway mpg they advertise never happens. Even if gas hits $2 I'd stay with the Prius.
I guess my only concern is "What has changed with either your back or The Prius seats?". If the 2010 was detrimentally uncomfortable...are you sure the 2014 will work for you?
Back is better and the seats in the prius v sit higher up than the regular prius. The doors are a little bit wider too.