I tend to echo Adrian's sentiments. I'll add some of my own, too.
Firstly, the Polygrade V RC paper's gradation is pretty similar to the FB's, IMO. Of course, the usual FB vs RC observations apply here as they will for all paper brands.
I do find that the ultimate transition from deep shadow to black is a little more abrupt than I would like. This isn't evident from the paper's characteristic curve (which looks like it was plotted by a high school kid using Excel if Forte's rather amatuerish data sheet can be believed) but it seems to consistently appear.
I really prize this paper for its toe. It's got a pretty lengthy toe with a relatively gentle upsweep (again, not that you'd notice it from the curve) and I find highlights are very easy to capture though overall highlight separation is not aggressive. It's definitely mellower than Multigrade IV and Polycontrast IV. Midtone separation is marvelous and I find the midtones and the lighter shadow particularly rich looking.
It's got wonderful toning behavior. If anything, it tones too aggresively (hint: mix your KRST at 1:20!) in selenium and sepia. I'd prefer a bit more time before the start of color shifting in selenium.
Also, despite seeming somewhat flimsy, I've found the edges can hold up to quite a bit of abuse or overwashing without delaminating (Kodak please take note!).
So what are it's warts?
Well it goes greener than I like in Dektol and perhaps a bit bluer than I'd like in Sprint PQ developer.
You really have to watch it in an RC dryer as it appears to be a thinner paper that curls more easily. The good news is that it will uncurl with a hair dryer or even exposed to ambient temperature relatively easily.
Overall, it's my choice for about 90% of my photography. The exceptions would be some portraits (where I want something warmer) or scenes where aggressive highlight separation is required.
Most of the FB paper's traits appear to be identical. It should also be noted that I use Arista.EDU paper and I consider it to be identical to Polygrade V.