Mmm...not sure if I can recollect which blogs exactly, but this is one link I've found since your email:
http://www.head-fi.org/forum/thread/397617/audio-quality-of-the-new-macbook-pro
I'm very new to DAC tech, and I don't speak digital signal processing very well. In my day, a great stereo was bought with all your student loan money, and I ended up with a 100wpc SAE integrated amp, Dual turntable with Ortofon cartridge, and Klipsch Cornwalls downstream of 14ga speaker wire. Party time!
These days I am imprisoned in a condo, so lung-contusing bass or glass-shattering soprano voices are things of the past. I'm very new to DAC tech and don't speak digital signal processing lingo very well. So, I've turned to excellent headphones (hearkening back to my philosophy of youth that great speakers are a must), a very good entry level audiophile tube amp, and what I thought was a good entry level DAC. I now know that, besides great circuitry (which was touted about the Headroom DAC), there is something called "implementation". I guess that's my next lesson in DSP-speak ;-)
Thanks for your comment, and I'll take your more informed opinion about the MBP DAC very seriously and give a higher end product a chance!