On the hobbyist level, from what little I know, it seems more important to make sure your dish is properly aligned that it is to worry about noise figure. In most aspects, you're talking about a few percentage points difference if any at all. A misaligned dish is going to cost you way more signal than that. I'm using a DMX741 C/Ku LNBF and am very happy with it! It's very good quality and I've had no problems so far, highly recommended!