You should just go for it. I've owned 2, and the ST11 is a great bike. I owned an ST1300, and liked the 11 much better. Every bike isn't a perfect match for every person. So if you're thinking about it, just do it.
If you don't like it? Resell it. STs hold their value well.
And don't let the weight fool you. You can hustle the 11 down a twisty backroad with little effort. The steering is very neutral, so you really don't have to wrestle the bike to make it do what you want it to do. The bike is deceptively fast. It's so smooth that there is never really a "hit" of power when you twist the grip. Just silky-smooth linear acceleration.
They take deer hits well, too. I drove my 11 onto the roll back after clobbering Bambi in the side at 60 mph. Insurance paid me more than I paid for the bike, I got to keep the bike, and then I parted it out for enough cash to buy the ST1300 with cash. Too bad I didn't care for the 13 too much. Good looking bike, just extremely top-heavy to me. Fuel injection was very twitchy which made for terrible low speed manuevers. The carburetion on the ST11 is seamless and buttery smooth. Carb syncs are easy to do as well.
Hard to go wrong on the prices you are talking about. Good luck with whatever you decide.