Bubblegirl,
IMHO a funny decision: ...if money was a problem, I would have opted for the Kenko Pro 2x...
...€/$ wise the cheaper, so easier to sell when you want/need to ditch or upgrade
...
...but that's from a 'very specific' Canon-user's point-of-view...
...IQ - wise it ain't much worse than the EF 2.0x II on the likes of EF70-200F-whatever/EF100-400's...
...but off course it is a different story when using the real long EF primes... :P
...YMMV, since I do not know it's history for Nikon? ... but I am all ears
...and BTW,
congrats on the purchase, and as you showed: when used wise it seems it *will* deliver, so it's good for *you*!
Kindest regards!
Max@Home