Decided it was time to upgrade from my 1999 Honda Prelude but was a little skeptical at first. I loved that car. Great handling, good power, unbelieveable reliability, the list goes on. After I bought the IS, all my skepticism was put to rest. Love the handling (although I had to get used to RWD again) performance, sexy styling and yes, even gas mileage. My IS gets about the same as my prelude. And we're talking about a 3.0L V6 compared to a 2.2L 4 banger. I was impressed. Traction is OK in the snow. Living up in Canada you need winter tires, but even with them and with both trac. control and snow mode on, the wheels still slip quite easily, but if you pay attention like you should, you'll be fine.
Love the styling the best. Best stock rims out there. Good combination of luxury and performance. The dash is great. Unique and functional. If you want solid performance with some luxury then the IS is for you.
The transmission with the MT needs work (when you shift from 1st-2nd-3rd you hear a "clunking" sound). It's the only flaw I notice, but talking to dealers and other IS owners, it doesn't have impact on reliability or performance. You just have to learn to shift a little differently and it goes away.