MFJ-335BM NMO Mount Hi Flux 17 ft RG-58/u PL259.
MFJ has been around for a long time and specifically sells to the amateur radio crowd. Most of their products are lower tier, earning them the "MFJ =
Mighty
Fine
Junk"
Standard NMO mount, and the nice thing about NMO is that you can usually buy an NMO mount from any company and an NMO antenna from a different company and they will work together.
RG-58U is standard coaxial cable, often used in mobile installations due to it's small size, flexibility and ease of routing.
PL-259 is your standard UHF Male connector.
LarsEn NMO high frequency Antenna Mnt. With cable FME Female.
Larsen has been in the antenna business for a very long time. They make antennas and mounts. That's what they do and they do it well.
Their high frequency line of NMO mounts will work with standard NMO base antennas, regardless of manufacturer. There's a center pad that can be removed from the mount that will expose the high frequency type connector. Using the HF portion lends itself well to using the mount for GPS and higher frequency (5.8GHz, etc) antennas.
The FME connector is a small connector that is well suited to routing through the vehicle. It's much smaller than the PL-259 connector. It's a good option for those that need to route the cable but do not have the tools/skills to install a new coaxial connector. You would purchase an FME adapter to fit whatever you need, likely an FME to PL-259 adapter.
So, which one do you need? It's up to you.
I've mentioned it before, I've got 30 year old Larsen antennas that still work as well as the day I bought them. I've never had an issue with a Larsen NMO mount.
Unless you are going to be running GPS or higher frequency antennas, you don't need the NMOHF style mount, but it won't hurt anything to have it. Not a big price difference anymore. One benefit to the NMOHF mounts is that they seal up the coaxial connection at the base of the antenna better than the non-HF style mounts.
As for the PL-259 vs. the FME connector, it depends on what you plan to do. If you are going to try to hide the coaxial cable, using the smaller FME connector is easier as it's much smaller, just a bit bigger than the coaxial cable itself. You will need to purchase the FME to PL-259 adapter to match your radio.
But, ideally, you want to cut your coaxial cable to just the length you need. In a perfect situation you'd just use the amount of coaxial cable you need, no more, no less. You'd cut the coax to length and install your own connector. If you do not have the tools and/or skill yet to install your own coaxial connectors, using a mount with a connector already on it is a suitable choice.
If budget is not an issue, go with Larsen. They make better mounts. If budget is an issue, MFJ will be fine for hobby use.