I think the kx030 is a much better machine than the kx27. Not much bigger in size but has extra weight where it counts and more importantly, vast improvements in digging power and aux flow which I felt the kx27 lacked. I think you will be happy enough with it.
And
@Smiffy is right - the U27 does drive the smoothest of the 3! Odd isn't it? What lets the U27 down is poor dipper power - same as the kx27 really.
I don't think the KX030 is a bad machine at all, and in terms of power, is up there with the JCB 8026 - but they are both at the top end of the towable weight class.
I think you'll get on with it just fine.
If we are talking about old machines we loved dearly.....
Then Hitachi need to bring back the zx30! And its smaller towable brother the zx27! Both great machines 15 years ago and still stack up to this day. The Yanmar BV25 was another class old bit of kit - the new SV26 isn't a touch on it in my opinion. The older Kubota 71's were brilliant machines with poor cabs - even for their time. You'd have thought leaving the rest of the body alone and just putting a new cab on would be simple enough but they cant leave it alone these designers!