The 518 is currently the best value for money among those with a straight, omnidirectional antenna. However, it can only be used with U-segment antennas, and while V-segment antennas can technically be used, they are not very effective. If you have obsessive tendencies, I don't recommend buying the 518+. The internal structure of the 518+ will vibrate and make noise when shaken, but this doesn't affect its use. In contrast, the 518 does not have this problem.😁