Re: HDMI cables
There real rules are…
1. As with any product category “monoprice” products are hit or miss. Cable construction properties like raw material quality and especially QC measures taken during manufacturing work toward this end.
2. Any cables ability to carry signal (voltage) relative to distance is based on the gauge of its conductors. I have seen HDMI cable using conductors from 28AWG up to 22AWG. Lower gauge means thinker conductors which results in longer run before you run into issues. Remember analog signals have a gradual roll off in signal quality related to distance. Digital signals on the other hand hold strong and then will have a sharp drop of into completely unusable.
3. As with any cable (especially twisted pair) lots of problems result due to the terminations at the ends of the cable rather than an issue with the conductors themselves. Most higher end manufacturers will explain what they do at termination and explain to you why they think that it is superior to other methods.
4. When a manufacturer claims of 1080i and 1080P based on there levels of cables the differences are usually that they make their higher end cables with thicker gauge conductors and/or more conductive materials.
5. I have had good luck with HDMI cables from Audioquest for 15m and 20m runs. They are not cheap but have never once caused a problem on the longer runs. As far as shorter cables (<2m) Audioquest, IXOS and "monoprice" have given me great performance and Monster Cables have caused Monster Problems.
6. As far as boosters I’ve never used them although I would match brands if possible as I would expect all the R&D from a companies booster to have been performed on their cables which should produce the best result possible baring that the product is just bad.