First , according to the review I read of the 8300 is was described as having the best gloss differential and bronzing performance with gloss fiber papers of the three leading insets. Is this your experience?
Second, is the black and white output from the 8300 superior to the 9900, when using the True Black and White software, that I would certainly be using? Unfortunately Epson has stupidly locked out the use of QTR in their new machines and ABW does not equal QTR capability.
Third- The new Epsons have outstanding resolution in their dither, does the Canon match that at a native of 300 ppi? It certainly must be close by the review I read, which is a real improvement over the previous models that were a little coarse.
It seems to me the only downside of the 8300 is its massive weight. Damn, my girlfriend and I were easily able to unpack and set up my Z3100 by ourselves. Looks like you need a whole crew to move the 8300..... can't have everything....
I haven't found either of the printers to be better with gloss differential, but I haven't spent too much time evaluating it either. If the 8300 or 9900 had bad gloss differential, I would have noticed it.
B&W output is about even for me, and I do quite a bit of B&W printing. I have used the B&W mode on both printers, and I have to say that I have just ended up toning my images in Photoshop and I print my images as if they are color images, so I am likely not getting the deepest blacks or longest print life either. I am going to install the True B&W software this week and will be taking a hard look at the results. This is something that I am excited about, I must say.
The 9900 prints are a little sharper, I suspect due to the variable dot size. This isn't something that I notice when I back away from a print, though, and isn't something that I think about for large prints. I would be something that I would think about for smaller, cut sheet sizes like 10x15" prints or smaller.
The 8300 didn't seem that much heavier than the 9900. If you have used a 9600/9800/9880, the new 9900 is much heavier and most close to the 8300 than the older Epson models. I have moved two of the 8x00 Canons, and yes they are beasts. What I love is that these suckers don't move when they are printing, unlike the HP Z series.
One thing that you haven't mentioned or asked about is the black ink switching. On the 8300 there is no switch, as there are nozzles for each of the black inks. On the 9900 there is a process that is similar to the switching on the 3880 desktop model. The process takes about 2 minutes and uses a minimal amount of ink in the process. It also exhausts the maintenance cartridge faster, because that ink has to go somewhere.
The 9900 is much better at printing cut sheets. It is a dream to work with in this regards. The 8300 isn't bad, but it is much much much better than how the Z series printers work with cut sheets.
You won't be disappointed with either printer, I have to say. The price difference seems to be closer than I had thought at $1250, but $1250 is still $1250.
