There are a lot of us who came to the Super_T from the FJR and I had both a Gen1 & Gen 2. As with the FJR, don't be surprised if you look for an aftermarket seat and windshield. Also like the FJR, there are plenty to choose from and they don't have to be too expensive.
The first thing that hit me was missing the velvety smooth hammer of the FJR's power. The FJR throttle is almost like an electric motor rheostat in the relationship to power delivery. The Tenere is a twin, so you feel the power delivery and the torque "curve" is essentially flat, so until you jumper the clutch switch wire (see threads devoted to it) a brand new Tenere motor is almost underwhelming. Do the mod and wait 1,500 miles for break in and it becomes plenty entertaining.
As for seating position, there is a simple $2 mod to flatten the driver's seat and once done, We did a ride from DC to Alaska and California in June and I'll take the Super Tenere as a long distance mount over the FJR any day. One person on the forum (sail2XX) has gone 52,000 miles in a year.
Our last 2-up big ride was 600 miles and after that one I was asked if I could flatten her seat the way I did mine, which was again no problem. My partner is fairly small and really likes the back seat of the Tenere. Personally, I find the cushion a bit narrow but she likes it and there are several companies now doing aftermarket seats.
Using the big square panniers is incredibly more practical than the odd shaped 34L ones on the FJR. btw - With the big boxes and a set of bars, if the bike falls over, you pick it up and ride on, then simply touch up the paint with a little can of Rustoleum. You don't spend $120 for a mirror and then start looking to buy mufflers and plastic.
You'll LOVE the traction control and ABS when you have your passenger on and are goofing around on wet grass or gravel. The electronics just WORK. The Tener is also much easier to work on than the FJR and has a bigger alternator to power heated gear, lights, etc.
The FJR looks better to me and has it's place. But I live much better with the Tenere and am having a ball.