Its says on the specs that RG-8U has a total run attenuation of 1.8,I checked RG-8X and RG-58 coax and the RG-8U has the lowest loss.So it looks like I will be getting the RG-8U.Nothing wrong with using RG-8X for short runs at 2 meters. That 'short run' thing is typically less than 50 feet, or for mobile use. There's no denying that RG-8X is easier to manipulate than RG-8. So just how important is ease of use to you?
That 'spec' chart for various sizes of coax is a very nice thingy to have around, or at least to compare different cables and frequency usage. Fractional differences just don't amount to anything significant, so don't get too wrapped up in that aspect. The numbers to the left of that decimal point can make a difference, but they have to be larger than 3 to be very significant.
It depends on what the application is. It's not a huge difference if you're just working through repeaters and local simplex. It's a big difference if you're trying one of the weak signal modes where every fraction of a db can make the difference. It's always good practice to use the lowest possible loss cable for any given application....I have about 54 feet long RG-58 coax and 75 feet long RG-8U coax,which one would be better to use for 2 meter ham radio.The RG-58 has a total attenuation run of 3.0 while the RG-8U has a total of 1.8. Is that a big difference?