The FG and VG series are two different antenna designs both electrically and mechanically. Here are the basic differences between the two models you mentioned:
- The FG1523 is 3dBd gain, while the VG1506 is 3.85dBd (6dBi-2.15=3.85dBd).
- The FG is factory-tuned with no user intervention required for a <2:1 SWR across the 152-156MHz range. The VG has must be tuned by the user, and the 6dBi models have a bandwidth of about 3% of the center frequency, so about 4.65MHz at 155MHz, or 152.675-157.325MHz. Don't concern yourself too much with the bandwidth if you are not transmitting; either antenna will work fine for the VHF scanner range.
- The FG construction features a fiberglass radome with the radiating element epoxied inside. This makes it pretty rugged and ideal ideal for icy and windy conditions. The VG is 6061 aluminum tubing, so I wouldn't use it for any environment with strong winds or icing potential.
- The FG has a recessed N connector, while the VG's connector is exposed.
- The FG will be a stock item at any decent Antenex dealer, but most will probably not stock the VG. The lead time on them used to be about two weeks, but I dunno how fast or slow things are running over there now that Antenex is owned by Laird.
- The FG lists for about $250, while the VG is about $210. Street prices should be less than that.
For most people in the $200 price range, I would recommend the FG1523 over the VG1506. It is more durable, easier to assemble and install, and it is factory-tuned so you won't need any special equipment to get it up and running.
If you want to save a few bucks and have just about as good performance, there is a model FG1505 which lists for about $165. It is similar to the VG1506 except the gain is 5dBi or 2.85dBd, and it is a stock item at most dealers.
Personally, I wouldn't buy the Hustler. They are not in the same league as the commercial antenna manufacturers. The thing just looks kinda cheap to me.
I hope that helps. Let me know if you have any more questions.
Jeff