Tbh I find IBL in Superfly much better than firefly - you have to deal with it differently: put the emission value up higher (if you're not using HDR maps you might need a value of +24, for example), but the lighting system seems to work much more realistically [especially with a few area lights in the mix] so it's worth the effort.

If you have objects in the way then yeah you'll have shadowing, but as long as you have enough bounces in the raytrace, the light will get round and the overall scene will be infinitely more realistic, because that's what happens with real light in the real world: put objects in the way and it affects the light....! IBL in firefly was always a bit of a fudge.