Well, my dad was looking at cars - naturally i went with him :P
The new 3 Series:
Basically, the drawback are the run-flat tyres that they use. Whilst they are useful if you do indeed pop a tyre and need extra mileage to get to a repair shop - they do cost ALOT to replace, compared to conventional tyres. Inside, they look a bit lame if you buy them and don't get Sat Nav/TV because the top line of the console looks bland and flat.
They drive well, last long but seem to overpriced when you compare them to a Mercedes-Benz, i'm afraid.
My dad ended up buying a Merc for the same price and honestly, whilst i love BMW's - he got more extras with the Merc and i reckon the aesthetics inside are much better in quality.
Hope that helps...