By Genie & Gary Anderson

With the curves of the narrow road coming quickly, we climb up the edge of Silicon Valley toward the white domes of the observatory on the top of Mount Hamilton.

The top’s down in the early morning sun, but the heater warms us against the spring chill as the 2008 Jaguar XKR convertible torques up the steep switchbacks of Quimby Road, its agile and quick handling belying its size and weight.

But is it worth the six-digit price? Let’s tally the votes.

The climb up to Lick Observatory and the drive out the unspoiled back roads behind Mount Hamilton puts two votes, for performance and handling, in the affirmative column.

The XKR is one healthy cat: with safety gear, sophisticated suspension and brakes, and electronics, it tips the scales at just under 2 tons. In spite of that, the supercharged 4.2-liter V8 puts out 413 pound-feet of torque to go with its 420 horsepower, which Jaguar says is good for zero to 60 mph in five seconds. That torque was more than enough to pull the car rapidly up the steep 7 percent curves on the climb toward the observatory, with power to spare.

The handling is impressive. Quimby Road is a narrow, often one-lane road clinging to the side of Mount Hamilton. Highway 130, into which it feeds, is about the same, showing the Jaguar to be incredibly sure-footed and agile. Legend claims that there are exactly 365 curves from bottom to top, but who has time to count?

The R-Tuned enhanced Computer Active Technology Suspension (ReCATS), made the car feel smaller than it actually is. We confidently maintained a fast pace up the mountain and, later, down the other side.

Our Saturday morning tour in company with other classic cars was on one of those windy spring mornings in coastal California with crystal-clear air. We must admit that we were torn between speeding up to enjoy the performance of the car and slowing down to exclaim over the succession of views of Silicon Valley unfolding below us.

Fortunately, we could compromise with a stop at the lookout deck at the base of Lick Observatory, built in 1876-1877 as a memorial and tomb for James Lick and still used today by the University of California as a working observatory. We shared the overlook with a group of competitive cyclists who use the steep climb to the 4,200-foot summit as a training ground, and another group of motoring enthusiasts who had come to experience the challenging curves on their Harleys.

The Jaguar’s sleek appearance, its clean lines with the soft-top up or down, and the lovely details of the lights and grille would put another vote on the plus side. We noted that both cyclists and bikers, though committed to the values of their respective modes of transportation, were stealing surreptitious admiring glances at the car as it sat in the morning sunlight.

We were not too happy with the straight-up-and-down angle of the lower front grille, a definite loss of the more streamlined nose of previous Jaguar sports cars. That negative must be blamed on the new European Union pedestrian protection laws rather than on Jaguar stylists, and all new models from every manufacturer seem to be suffering equally. On the other hand, full marks to the lovely details of the carefully crafted grillwork and front lamps. We’ll leave it to the individual voter to decide whether the new decorative metal side-marker shared across the Jaguar lineup should go in the positive or negative column.

The convertible top fits well into the overall styling of the car, and its automatic operation is well engineered. Push the button and the boot lid flips up from the rear, with the top folding down quickly to stow neatly under the lid. On the negative side, when the top is stowed it takes up valuable trunk space, leaving barely enough room for one golf bag or two roll-aboard suitcases.

Put the top up, and although it provides good weather and noise insulation, the broad rear “C-pillar” area and the small rear window dramatically limit rear vision. Still, it’s a great improvement on the first-generation XK convertibles, whose lowered tops had to be manually covered.

Mixed votes on the convertible compared to the coupe – it’s nice, but there are definite trade-offs. Frankly, unless we were absolutely certain we were going to be doing most of our motoring on clear, sunny days cruising around town or on scenic back roads, we’d give serious consideration, instead, to the coupe.

The interior is classic Jaguar, with a pleasing use of leather upholstery and wool carpeting accented by tasteful use of attractive wood trim on the fascia.

The seats are comfortable and supportive. We’ve complained for several years that the previous-generation XK’s handling couldn’t be fully enjoyed because driver and passenger would slide back and forth for lack of seat bolsters. Side bolsters on the new sport seats are effective and can be adjusted by a switch on the seat control panel.

Unfortunately, we have to put a vote in the negative column for the detailing of the interior switchgear and displays. Compared to several other high-ticket enthusiast automobiles we’ve driven recently, the mixed shades, colors and textures of plastic on the switchgear seem to be borrowed from Toys“R”Us rather than Cartier.

This is probably more the fault of the Ford accounting department than the Jaguar stylists, but we hope that Jaguar’s new owners can find some rupees in their purse to fund new switchgear that is more like Mercedes and Bentley than Ford and Mazda.

Giving weight to the negative interior vote, the unhooded navigation screen is nearly invisible in the glare of sunlight, which can put a damper on top-down exploration of little-traveled backroads.

After a visit to the observatory, the rest of our Saturday morning tour took us down the back side of Mount Hamilton and north on San Antonio Valley Road, through ranch-studded countryside that is as unspoiled today as it was when it was the backdrop for Tom Mix and Hopalong Cassidy adventures in the early days of movie-making.

We stopped for hamburgers at “The Junction,” south of Livermore where San Antonio Valley Road meets Mines Road and Del Puerto Canyon Road. There we shared the parking lot with a motorcycle club in Merced M.C. leathers and a sprocket of cyclists in spandex club jerseys.

Over burgers and fries before the final leg of our drive north to Livermore’s winery area, we toted up the votes and agreed. This R-enhanced Jaguar from the latest generation of XKs is a fine automobile, with more votes on the plus side than the negative of the ballot. Against the negatives of convertible limitations and interior detailing, powerful performance, cat-appropriate handling, sleek styling and interior comfort just barely carry the votes.

Gary and Genie Anderson, Los Altos residents for more than 20 years, are co-owners of Enthusiast Publications LLC, which edits MC Squared, the MINI magazine, and contributes articles and columns to a variety of other automobile magazines.