I haven't had the opportunity to shoot the new little Kimber Ultra CDP, although I've briefly handled and shot one of the earlier Ultra Ten II (internal extractor).
As with many diminutive 1911-type based pistols, that pistol seemed to almost exhibit a preference for who was shooting it.
In the owner's hands ... a rather large, very strong individual, FWIW ... the pistol didn't exhibit perfect reliability when being fired with our standard W-W 230gr loads. In my hands, however, it seemed to function just fine with the same ammunition. Another instructor made the same observation regarding the pistol's functioning when being fired by the owner and the other instructor, too.
If it were me, I'd also restrict my ammunition to standard pressure loads in that little pistol. I'd also make sure I replaced the magazine & recoil springs as recommended, too. I tend to replace the mag & recoil springs in my little .45's sooner than most folks.
Then I'd try some of the different defensive ammunition marketed by the major makers, and decide upon whatever bullet weight & design suited me among those that exhibited reliable functioning in the new pistol.
Pretty much what you probably did with the Officers the first time, right?
Personally, I happen to like the standard pressure RA45T for their folded petal design which protects the nose cavity during feeding & chambering, as well as the leading edge of the lead core during expansion. My next choices are either Gold Dots or non-bonded Golden Sabres.
Lots of good designs and product lines out there in the current ammunition market, though ...
Whatever happens to suit you for functional reliability in your new pistol, while you're shooting it, is the primary consideration, however ...
My Officers ACP happens to feed anything I've ever tried, although it's been modified and tuned just a bit.
I had to really resist the urge to buy a new Colt Defender when I ordered my stainless XSE Government, or the 4.25" SW1911PD when I decided upon a SW1911Sc 5" ...
The little .45's have an appeal, especially for CCW/off-duty usage, especially when incorporating polymer & aluminum frames ... but I've already got an Officers, a CS45 and a 4513TSW to cover that inclination ... for now.
The .45GAP-chambered G39 is sort of interesting, but I'm content to wait until it's been wrung out a bit in actual "market-place" shooter's hands for a year or so ...
Congrats on the new pistol ...