The Holland UVSJ would be appropriate as a combiner when you have one antenna serving only UHF reception and another serving only VHF. None of the satellite diplexers would be useful as OTA antenna combiners. Regardless, I can't see any point in worrying about tenths of a dB of difference between different vendors' UHF/VHF combiners.
If you
need to overcome the loss of the UHF/VHF combiner, equip each antenna with a preamplifier of it's own (this would be an extreme situation). The gain of the preamplifier will overcome the noise margin 'hit' of the combiner provided the preamplifier is upstream of the combiner. The same is true of cable and splitter losses. If the preamplifier is upstream of the loss, you can ignore the loss and subsequent cost in NM.
Another way of saying this is, The noise figure of the first amplifier in the system is the most important NF. Even if you have long cable runs with many splits, you can overcome all that loss with properly selected amplifiers placed in appropriate locations in your network.
Example:
http://forum.tvfool.com/showthread.php?t=13659