Ah, you still need to ride mine, I wouldn't make too many assumptions until you ride another 919. The unstable handling you mention is unique to that individual bike, ask him how mine felt.
True Scott, this was a cut and paste job from when I rode Nathan's bike initially a month ago. Getting to ride a 919 that is properly set up could make a world of difference. There were several factors that prompted me to buy the S3...
1. The power: I fell in love with the way this thing makes it's power. The power band seems to start at 2k rpm and keeps building steadily until about 9,000 rpm. All in-line 4's I have ridden seem to have a point where it "jumps" into the power band. I felt this was harder to ride in the corners where you can skid the rear tire by jumping on the throttle too hard.
2. Exclusivity: I have only seen one other S3 in Indy in the past year of riding. The 919 while still not common is made by a common brand and I get into more parking lot conversations with people who either have no idea what a Triumph is or old guys who didn't realize that Triumph still made bikes. To me it has the exclusivity of a Ducati but doesn't come with the higher price tag and the stick in the bum mentality.
3. The sound: Riding affects all 5 senses and the aural enjoyment I get from idle to full throttle is very stimulating.
4. The price: I bought my 06 S3 with 3,000 miles with alot of accessories for $6,900 last year. I had just gotten an inheritance which would have allowed me to buy anything I wanted for under $20,000. I had spent a year of researching magazine articles and internet sites as well as test rides to boil down to the S3. I felt I got a pretty good deal and still had plenty of cash left over to further enhance my bike.
5. Personal preferance: The hardest point of all to explain... The Speed Triple excites me to just look at her. I would be happy to ride it in stock form which to me says alot about a bike. I love the lines and the even the headlights. I love the mechanics of the bike and the engine design is just so different than just about everything else out there. I knew I wanted a naked and with so little to choose from, this was the one the tickled my fance the most. I could have been satisfied with any of the liter nakeds on the market today, but the Speed Triple was the one that I can honestly say I will probably ride to its grave and then buy another one.
The 919, while a great bike, had too many things that I would have wanted to change right after purchasing. Exhaust, tuning, handlebars, rearsets, gauges, suspension, blah blah blah. The S3 needed a louder exhaust (I went with Trident exhaust after selling the Arrow 3-1 system the previous owner bought), bought a Tuneboy (similar to the power commander but with even more adjustment capabilities, the handlebars are perfect for me, the foot pegs are perfect for me, the gauges are digital and offer a wide variety of info missing from the old school gauges on the 919, and the suspension is stiff enough for sport riding but doesn't beat me to death. The majority of changes I have made to my S3 have been cosmetic (flyscreen, bellypan, mud guard, powder coating...)
Long story short, the S3 just fits my priorities the best...