I test drove the IS250 last weekend. My thoughts in comparing it with a 325i/325i Sports:
1. Acceleration - good but not as good as the 325
2. Handling - seems ok, but dislike the lighter steering typical of Japanese cars
3. Exterior looks - good, about on par with 325
4. Rims - I think they'r 17", prefer the 18" on the 325i Sports.
5. Interior - like the perforated leather seats with built in aircon - good for our hot weather, but maybe get dirty easily? In general, prefer the 325's interior look though.
6. Dashboard/electronics - some fancy lights in the dials, can see your gears as your gearbox changes, paddle shifters (nice feature, but how often do you actually use it if you're mostly a city driver?), no big LCD screen (Lexus didn't bring in the GPS & big LCD screen), great sound system (but then again, my ears aren't that refined to care about it so much so long as the sound is decent enough like from our E90's standard sound system), wood trim (I dislike wood trim, so a plus for the E90 here, although I was told there is a titanium trim available as an optional aftermarket accessory).
Price-wise: Can't remember the exact price but it's somewhere between 305k and 313k. Sunroof is an additional 7k.
I think it's a nice car, but overpriced relative to the E90. Might pay maybe 250k for it, but for the current price, I'd rather have the 325i Sports for about the same price (M-body kit, GPS, big LCD screen, 18" rims, better acceleration, heavier steering).