Well...a few days ago, we saw Nikon come out with their newest telephoto lens - the long awaited Nikkor 300mm f/4E PF ED VR to replace their very long-in-the-tooth but very capable AF-S Nikkor 300mm f/4D IF-ED. The Nikkor 300mm f/4E PF ED VR has added VR to the mix as well as a Phase Fresnel lens to cut down on chromatic aberration and ghosting. If London Drugs or Broadway Camera get a sample lens to try, I'm going to get a couple of shots with it just to see how it is. My prime 300mm will be the f/2.8 VRII, but I'm liking the size of the Nikkor 300mm f/4E PF ED VR which is dramatically smaller than the lens that it replaced. Let's just say Nasim Mansurov at PhotographyLife blog has offered up a size comparison. Go to his blog and take a look. That means that lens will be able to be handheld easily which is great for long hikes through rough terrain and that lens can still take a 1.4x or 1.7x teleconverter easily. I don't know how a phase fresnel lens works so I don't know how it will affect using an aspherical TC-20EIII, but I will test that out too when I can get my hands on a workable copy of this lens. Outside of my disagreement with Nikon on the fact that pro-DX still has a market to cater too, I find the lens offerings from Nikon to be very nice.
My own personal opinion is this is a lens that is very useful to the outdoor photographer on a budget. But since I shoot in dark dim arenas, the only time I'd be able to use this kind of lens is when I'm going outdoors to shoot. It's still useful for sports photography if lets say that you are shooting for an outdoor trackmeet, but still the f/4 aperture will mean that you will have to put your ISO higher and get your shutterspeed up to freeze action, but overall, this lens is well worth looking into and may be an alternative to the f/2.8 VRII version which will set you back over $6K CDN.