Need help picking C5 A6 or 02-04 A4?

[Rob]

Mulling over what I want to get next to replace the 12v6 A6 that was my
daily driver.

I am leaning towards the A6 2.7T w/6 speed.  Any particular reasons why
I wouldnt be happy with this car?  Any known problems to that platform?

I was told the 3.0 was something to avoid. Is that because the 30v is a
mechanical nightmare of a head?

I do all my own work, have VagCom and am very familiar with Audi having
had 4 type 44's and 2 12v V6 C4 A6s.

My other potential choice could be 02-04 A4 1.8t.  

Anyone wanna give me some pros and cons of each? 

Thanks!

Rob