SBG is good within their focus. Remember, that their focus is inexpensive yet serviceable swords (often called "beaters"). Their reviews are usually fine but are sometimes apparently written by folks who don't really know how a sword should behave when in use. Consequently you get, from those particular reviewers, information about how much "authority" a sword "has" when you swing it but not really any good information about it's serviceability, how well it handles characteristically in comparison with historic and applicable techniques, etc. You will get a lot of water-bottle tamishigiri (which I actually happen to like) but that doesn't tell the whole story. In fact it's often misused or performed without martial or training goals (not that there's anything wrong with test-cutting "just for fun" but it ignores the whole point of test-cutting --- I also have a rant about swords specifically designed to perform well at test-cutting at the expense of other attributes that a sword should have).
So, while SBG is a good place to use as a data-point (I read it myself), I'd back that up with personal experience or information from at least one other source. Avoid any SBG reviews that start something like, "I'm new to swords so here's my first review of the Massive Death Cutter from Wizbang Manufacturing..."
SwordForum is a fine place as well, but bear in mind that they're not always the end point either. It has been noted in the past that they often seem to have a cliquish feel or a general "mob wisdom" in which the general consensus on a particular point tends toward one or another "side," especially on contentious issues.
Don't get me wrong, SFI is a great site and I'm friends with any number of members and respect them greatly. It's just that like minds tend to congregate. You could easily go to alternate forums and get a general consensus that swings the other way on some of these contentious issues. (personally, I tend to "like mind" with SFI more than with the other sites, but I want to be honest)
As one data point, you should try to find out the weights, dimensions, and "handling characteristics" of historic pieces from which the reproductions are copied. Often the weights, distal tapers, or point thicknesses are vastly different on the reproductions (frequently for very good reasons). Craig Johnson and the Oakshot is a really good source for any number of these, particularly the medieval though I know for a fact that Craig has modified some Civil War Saber reproductions to more closely align with historic examples for his own personal use.
MyArmory.com is also a good place to go to get some information or another opinion.
In short, it's all about "doing your homework" and SBG is a fine place to get PART of that homework done.
Peace favor your sword,
Kirk