I have owned both Silaflex and Browning Silaflex rods. Here's my opinion FWIW. Sialflex was way ahead of their peers in the 60s and built blanks that were lighter and more elegant (generally) than their competitiors. The rods were comparatively expensive at the time ... running about $60-70, while a Fenwick cost half that much. The rods are graceful casters, well constructed and have, I believe, the best reel seats made at the time. I found the grips to be a bit fat for my liking. A friend who should probably know told me that the Silaflex rods and the Brownings that followed them were the first S-glass rods, but I am not sure. The Silaflex I had was an MF-75-2, also called a "Cutthroat" for a 5 wt, if I remember correctly. I found that rod to have more wobble in it than I wanted and after describing it well on eBay with nice pictures of a high quality, very early, light line trout rod--it sold for over $200. You can tell the Silaflex rods easily, they have a seahorse on the label. I also believe that the Silaflex rods had the guides that were two wraps of material ... like a small section of a spring, similar to many of the Phillipsons of the day. All the Brownings I have seen have normal snake guides on them. Both Silaflex and Browning rods will be clearly labeled if they are in good shape. Browninig-Silaflex rods do have a small seahorse on the label but Browning is clearly emphasized. The serial numbers as discussed here are another way to tell.
In the very early 70s Browning bought them out. They changed some things and they kept some things. The rods look very much the same. Same slow, near parabolic action, same great reel seat, same translucent brown blank, and same tan and brown wraps. I like them better than the Silaflex I had. They dampen better with the same classic slow action--probably an improvement in taper and construction materials as the industry marched through the 70s. In general, I find that I like the rods made between about 1970 and 1975--great materials for best performance but before the environmental limitations restricted the type of materials and waste that the companies were allowed to produce.
The earlier Brownings have serial numbers like 222960, and 222975 where the last two numbers describe the length of the rod, they are generally 5, 6, or 7 wt depending on the length. I have the 22970 (7 ft 5 wt) and 22980 (8 ft 6 wt). These rods have metal ferrules, both are great casting rods and they can be had for a reasonable price. The 7 ft 5 wt rod is a great small stream rod, and the 8 ft 6 wt rod is terrific for smallmouth whether wading or floating.
Still later, as glass ferrules came on, Browning incorporated them into their line and, I believe, the serial numbers for those rods changed the first 2 to a 3 to identify the series (322970, 322975). These are probably the most sought after of the Browning rods as they do not have a metal ferrule. The finish and appearance are nearly identical to the 2 series rods and remain almost identical to the original Silaflex finishing and wrapping. I do not own (nor have I cast) any of these later rods but would pick one up, given the chance, just for the glass ferrule feature.
I had purchased the Silaflex rod to fill the 7 1/2 ft hole between my 7 ft and 8 ft Brownings and did not find I liked it as well due to more wobble, less dampening, and slightly softer casting (even though I am a slooow rod guy). Make no mistake that the Silaflex is the more collectible rod, which is why I sold it to allow me to buy other rods I'd rather fish. They are harder to come by, less likely to be found in excellent condition, but they are a great piece of fly fishing history.
So, I guess I'd disagree with your friend. I think a great Silaflex is probably worth more--but a glass ferruled Browning from the mid-70s probably represents one of the best production rods from a top of the line fiberglass rod company at its prime. The metal ferruled rods are also terrific and can be had for a bit less cash.
If I could find a 7 1/2 ft Browning without a metal ferrule, it would be my next purchase. The best rod for your Virginia fishing environment would be the 322980 which would fish a 6 or 7 wt line.
Hope this helps.