Certainly not a bad engine. Plenty of power to be had with a k04. But I just found them lacking a bit of soul.
Saying that, mine was an early k03 engine, so hardly the pick of the bunch. I went round Oulton Park in the Shark Performance mk1 Octavia (BAM, anti-lag mapping etc) and that thing pulled hard.
But compared to the performance of a k04 TFSI it's a different game completely.