I bought my Hobie PA-14 in July 2013 because it has the Vantage seat. The seat in my old 2010 Hobie Outback was a "pia"!
The Vantage seat is very comfortable and easy to adjust and make it "fit your position preferences".

I have never had any back pains.

My legs do get a bit tired, after 4 to 5 hours of solid trolling with a down rigger, 4 1/4 pound weight and 5" quickfish lure, underwater depths of 25' to 75'. I typically cover 7.2 to 9 miles.

I found that drinking water and eating a Cliff Bar (energy bar) and sandwich is critical, as my body burns many calories while trolling. The exercise is a very good way to lose weight and or stay in good physical shape, if that is one of your goals.

Due to a nasty mc vs semi crash in 05, I'm sporting shoulder replacements, knees need replaced, 3 level cervical spine fusion, L5-S1 discectomy, a bunch of healed compression fractures throughout thoracic spine, elbows are shot and so on...in other words, it's a good thing I'm not a horse.
Back pain has been miserable for many years, but purchasing my Outback 180 has been the best physical therapy (and mental I have ever experienced.
The more I peddle about and fish, the better my back feels. I spend hours on end every day on the ocean fishing. The only days I stay off to run errands and chores (usually the weekends when it's more crowded on the water), my back & joint pain increases. I highly recommend giving it a shot, after a month of daily Hobie use your body gets used to exercising without impact or the grinding in the knees when riding a bike and you'll really start enjoying it to the level of becoming addicted (fair warning) to Hobie therapy.
Pura Vida,
Natalie