I did not get the ToonTrack one (yet). I may. I have EZKeys and I did get the Gospel pack. Do you have NI's other upright? If so, how does TT's Upright compare to NI's Upright (not The Giant)?
Admittedly I'm not as hot on pianos as I am on drums. Jeez, I have too many drums. Wait did I just say that? Click on the Me in my sig (then select Studio) and you be the judge. LOL! I think you probably win the "I have more than you" contest, but I'm actually not that too far behind you. I'll have to write a list of all my stuff and we can compare.
I haven't played that much with the EZKeys upright, but if I had to say just off the top of my head, I think The Giant has better samples.
But the one think I like about EZkeys is the patterns and the intelligent design of chord circle. I'm not much on music theory (I studied it many decades ago and have forgotten much) but the chord wheel on EZKeys lets you change chords and patterns and suggests the best choices for you. But I'm sure you already know all of that. I'd say the EZkeys upright is close in sound quality to The Giant, and EZkeys has the chord patterns but The Giant has more efx and controls, which allows you to really get in there and adjust everything from the hammer and pedal sounds to tweaking it's EQ, Compression, Reverb, and all that other good stuff.
Both are definitely better than the NI Akoustik Piano (Upright Piano) that came out in 2009.