Good news, I'm leaning towards the same seat. I have no major problems with the stock seat, seems to work decently with my posterior, but the solo seat is a lot more elegant for riding one-up. Looking good there.
Only problem with the solo seat and solo luggage rack or back rest is that my legs aren't the longest (nor am I the most limber guy in the world), I tend to just throw my leg over the rear of the bike to get on. Not sure how to get on with stuff preventing that, some sort of clumsy one-legged hopping...?