A bit late in on this conversation but I'll add my thoughts, because the short answer to your question is Yes. In my opinion.
With the B7, I had 2 examples and really loved them covering nearly 50k miles between both over a period of 3.5 years. I've now had a B8 for 8 months and covered 12k miles in that time and love it a little more than the B7's, and I've had some frustrating times with my one! So I'll break it down into category’s.
External looks:
The B7 is a classic and has aged exceptionally well and still looks fairly current; the stepped front headlight really helped this I feel. However the B8 takes those good looks and evolves them just a bit further. The front bumper is even deeper and the boxed rear arches are a real thing of ‘poster pinups'. With the Audi brand polish, it all adds up to a subtle yet purposeful package. I was really considering an RS5 but the looks were just too weak when compared with the B8 RS4; parking them side by side it becomes even more evident.
Interior:
My B7’s both had buckets as the comfort seat option was naff; the buckets really made you feel connected with the car. Drawbacks were the wear rate being far higher, as even the most diligent of owners would still crease the bolsters leading to a shabby looking seat. The B8 Supersport seats on the other hand, were a good compromise between the Buckets & Comfort seat options for the B7. They look more grown-up and are far easier for the more rotund and elderly relatives, I occasionally carry in the vehicle. As a rear seat passenger, the Supersport seats allow for a better and more comfortable experience. There’s more legroom and better front visibility.
I had a sunroof in one of my B7’s and it’s an option that I really like, in many ways. The B8 Panoramic Sunroof has moved the game on further, being larger and operating in a similar manor, whilst the sunblind still allows some vision but blocks out the harsh light and/or debris. You can be bathed in light with all the practicalities that a black interior affords.
Engine:
Well…what can I say! It’s the last incarnation of this wonderful high revving, naturally aspirated V8. The B8 offers more power and from the odd dyno sheet I have seen, appears to suffer less from Carbon build-up. They hit the numbers which infuriatingly the B7 didn’t. On the road the B8 feels and is faster but that can also be attributed to other areas like gearbox, speaking of which.
Gearbox:
Changing to a B8 and losing the manual gearbox of the B7 I felt was going to be the hardest aspect for me to adjust and become accustom too. I love a good drive out and the ability to heal and toe keeps you thinking and feeling the car. However the S-Tronic is a very accomplished gearbox with super gearchanges when ‘on it’ and I don’t feel cheated by having to flick a paddle in manual mode. Being a 7 speed unit, the ratios are a bit closer together which helps tie in better with the engine character and keeps it fizzing away. The B8’s 7th top gear is longer than the B7’s 6th top gear, so motorway cruising is a little more refined and helps to eke out the petrol tank range for an additional 50-80 miles. In auto mode around town the S-tronic is a perfectly good gearbox, perhaps not as refined as the ZF8 you find in the C7 RS6 but the S-Tronic gear changes are quicker and sharper.
Handling:
I’ve taken both the B8 and B7 from the Southdown’s to Scotland and the Yorkshire Dales over to Wales. We have some awesome roads over here and I love to explore them whenever I can, in all sorts of weather. The breadth of ability both these cars have, is what makes them special and with inclement weather we often get. The RS4 just chews up roads. Over all, I find the B8 a tad more agile at slower speeds, the torque vectoring and sports differential really help to get the car into and out of the apex better. All within reason though, as it’s still an Audi.
The hydraulic steering of B7 is now the aspect which I really miss the most. Even so, having come from BMW M cars the B7 isn’t exactly up there as a steering ‘great’. The B8 however, is a bit woeful in the feel department. You can place the car on the road perfectly fine; just don’t expect your fingers to become alive with feedback.
Suspension:
All of my RS4’s had DRC and the B7’s had the Supersport option, I love it and wouldn’t be without it. The body control and compliance that DRC delivers is really great. The Supersport option on the B7 is equivalent to the B8’s Dynamic mode, yet comfort mode in the B8 offers something that the B7 just cannot do – waft along. It’s great that at the touch of a button, you can change the character of the car to your own chosen mood and passenger accompaniment.
Technology:
The B7 is a little antiquated now but not badly so. With sensible modification you can diminish the gap between the two generations a little bit, more so with the connectivity. Some people are now even saying that the B8's tech is becoming old, which I find hard to believe. There’s more specification differences available on the B8 compared to the B7; so perhaps those finding the B8 old have less kitted out cars? The only tech thing I felt missing from the B8, is a head-up display option.
So that's my ramblings on the two
The B8 community will steadily grow, as the entrance price decreases and they start falling into more enthusiast's hands.