2 vs 3? kind of a wash. 2 is a bit "cheaper" but 3 is a bit more "flexable", but even that is debatable. What isn't easily debatable is they're both good airplanes.
That whole class of design (AXN, Skysurfer, Bix 1/2/3, Explorer . . . ) tends to be very friendly to new pilots and good planes to go out and just fly. The 2, being a belly lander, is a bit less flexible for touch-n-go's on all surfaces, but should land well anywhere, and both are small enough to hand-launch. The cockpit and fuse layout is a bit more accommodating in the 3 than the 2, but while it's a building challenge fitting elaborate setups in the 2, it's been loaded up many times in clever ways -- not as easy, but not impossible.
Only big "this v. that" I can see right now is availability. I'm assuming with your quads you have your own radio gear, and I don't see a PNF (only needs radio and battery) Bixler2 for sale at HK in any of the warehouses. The ARF (needs all electronics) for either is for sale in the some of the warehouses -- not a bad option if you want to spec your own power system. Alternatively they're both available as RTF (needs nothing) at various warehouses, but the junk radio they ship with it is . . . well . . . junk.
A while ago I wanted to make a nice FPV plane I could cruise around some of the corn fields and parks with. I wanted something larger than the bix 1 I have already. I went with a Bix 3 because of the spacious inside and the landing gear. Hobbyking sells a PNF version where all you would need is radio, receiver and battery.
I didn't have a drone with bells and whistles, it was a Chinese JJRC H8C drone. It hasn't got a seperated receiver and I can't program it. I'll probably buy a Bixler 2 and just have fun with it. Thanks for helping me.