I've had an A4 from each of the previous three generations- a B5, and B6, and most recently an '07 B7. All have been the four cylinder turbo quattros with manual transmissions. My current one goes off lease Wednesday. I've already replaced it with a 2010 GTI.
I did seriously consider a 2010 B8 A4 as well. I had a few issues with it, not the least of which was the price. Specced to the level of my current Audi I would have needed to get the Premium Plus package, which doesn't include a few amenities my '07 model has such as adaptive headlights and self dimming mirrors. It would add Bluetooth, though, which my car doesn't have. But even at that the sticker price is about $5000 greater than my '07 car. The lease deals weren't as competitive either, even including owner loyalty money. And I have a great relationship with my dealer and am used to getting good prices with a minimum of negotiation. I guess Audi's just not pushing their leases right now.
Another problem that kept me out of a new A4 is the difficulty in sourcing a manual transmission. Almost all of the A4s on the dealer lots are autos, and I didn't have time to order one. I did get a chance to test a 2.0T Quattro 6-spd manual with the Sport Package and it was much more fun to drive than my car. In fact I got a speeding ticket. The extra torque made it feel much closer to the GTI in speed than my current 200hp A4. And the handling is better, too, than my B7 model.
On the plus side, with all the snow we get here in Erie, PA, the Quattro system has been a real life saver for me over the years. But I went for the GTI anyway. For me, I was willing to give up the Quattro, as well as some features like Homelink, rain sensing wipers, and leather, to get the livelier performance and tighter handling of the GTI. Any way you slice it, the GTI is a better drive in good weather, handles well enough in the snow, and is only marginally less comfortable and refined than the A4. The GTI has an emotional appeal you just don't get from the Audi. Hell, I'd have bought the GTI for the steering wheel alone. If I could have plumped for the S4 I might have picked that, but against a 2.0T I'd take the GTI every time...
-V