I have a 3320 ordered equipped like your 3120, except I went with the 447 hoe. Did you order the deluxe hood guard, or is that the one included with the CX loader? I noticed that JD's configurator lists 3 (hood guard, deluxe, and deluxe attachment). I didn't think about it when I ordered mine - just went with what was included.
My dealer didn't have a 3120 in stock. I drove a 3203 and the 3320. Since I would have had to wait an extra 3 weeks for the 3120, and also since it was only $810 extra, I decided on the 3320. (No backhoe option for the 3203) I'm sure the 3120 would have been just as capable for my use.
That's one good looking rig.
I considered the 448 hoe, but 7 1/2 feet is deeper than anything I'll be digging, and I'll be in the hills a lot and figured that the bigger hoe would be a lot of extra bulk and weight to lug around.