Example of how penguin affected me...
I don't have a single site that lost anything to that update. If anything they only got busier. If anything dropped between April and June it was a normal drop. I'll add more links and have it right back by August...
But for the most part... I actually received more overall because I have hand written content. I have very few purchased links. The links you see on my blogs are real trades.
Sure, Google likes inbound links more than A <=> B straight trades... But Google also likes to see a realistic ratio between the two! Keeping that in mind I have lots of inbound links, lots of outbound links and even more A <=> B trades within each blogs niche.