It's an analog adapter. In analog technology, you need good cables and shielding, else the image on the screen distorts and doesn't look nice. I bought my adapter from Apple when I purchased my Mac Mini.
When it comes to analog audio and video, the best you can buy isn't good enough. Everything else is good with cables/adapters from eBay.
Well I bought a mini to HDMI/DVI/DisplayPort adapter about 2 weeks ago from a power seller named "all cable adapter" on ebay. This 3 in 1 ended to be cheaper than most of the other DVI only adapters I found (even if it shipped from Hong Kong). The quality of the thing really impressed me (for that price I was expecting mostly a not-so-good-looking-but-still-working kind of adapter) and it shipped faster than many other orders I made from the US (and actually shipped faster than another order I placed on the same day, shipping from ontario (canada) to me in quebec (still in canada)...)
I ended up plugging my display on HDMI and it works just fine.
The only bad feedback I can give to that seller is the more-than-poor quality of his english.. but hey; this guy comes from hong kong...