It doesn't matter if you are a coach, CEO or motorcycle designer, following a highly successful predecessor is tough, especially if you are tasked with going in a new direction. When the Ducati 999 was introduced most Ducati fans had one response; WTF? Where the predecessor 998 had kept the classic design of the 916, the 999 was a step in a new direction. Penned by designer Pierre Terblance, the 999 was mechanically superior from its predecessor but its oddball/rounded front fairing and exposed rear seemed a bit disjointed.
But the point of the 999 wasnt just to go into a new look/design direction. Ducati wanted to win AMA superbike in the USA, which it hadn't done sine Troy Corser in 1994. While the 1st generation base 999 and 999s had the same engine as the predecessor 998, the 999R and 2nd generation 999 models came with a new engine with a completely new cylinder head design, with revised ports feeding larger valves made of lightweight titanium, larger intakes and exhausts, more aggressive cams, etc. A detailed explanation of the differences in the engine can be found here.
The 999R was a typical homologation bike; lots of stuff that was good for the track including the bonkers new engine and carbon fiber bodywork, not so great as a daily commuter and a high price tag with only 300 units.
As the folks at motorcycle usa wrote
Hands will go numb after about 30 freeway minutes, but that's a fault of the clip-ons forcing an awkward wrist angle more than from any sort of engine vibration. In fact, with the motor's lighter reciprocating and rotating masses, this might be the smoothest Desmos we've ever sampled, and it positively loafs along at a lofty 85 mph (or higher). Our 999R might also have had the nicest shifting gearbox of any Ducati. Ergonomically, we appreciated the taller windscreen fitted to the 999R; not only does it offer a bit more protection from the elements, its upper edge no longer obscures a rider's view of the gauges.
So whats it worth? Well this particular 999r appears to be basically new with only 125 miles but it is almost 10 years old so some servicing could be required (including the infamous Ducati belts). The 999R was originally offered for right around 30k but recent auctions/posts on RSBFS seem to have prices ranging from 13k to 18k but those were higher mileage bikes. The opening bid price of 15k and Buy It Now price of 23k would seem to indicate an actual reserve somewhere in the middle, maybe around 18-19k which is right in line with previous auction prices.
NOTE: The seller is not showing a clear picture of the mileage so this should probably be verified before purchase