Yes, Airspy uses the same tuner-on-a-chip like RTL SDR dongles, the R820T, which incorporates a tracking preselection stage. Such a varactor preselector is good enough for broadcast purposes, but marginal for radio-minded people looking for unknown weak signals.The website claims "Tracking RF filters" but I don't recall seeing details of them.
On my Winradio G33, I have control over them, but I haven't seen any info regarding Airspy.
There are some SAW filters on my FCD Pro+ which work well.
I drool when I see FCDP+ !!!Maybe it was all 'AirWare'
By the time these guys get their act together, Funcube will come out with Mk3 and blow them away.
The FC people have already produced two successful commercial SDR receiver products in the last few years. They obviously have the talent to design, build and produce good product that is sold all over the Globe. If they are keen on staying in the marketplace, I'm sure that Mk3 is already on the drawing board, if not at the beta testing stage.
The FCDP+ is a pretty amazing receiver given its size, so I can't wait for the next version. Hopefully, with a wider bandwidth capability.