Overall I pretty happy with my 1450 loader. I like the mounting, controls and lift power. I also got the optional quick attach bucket (nice feature).
I felt my 1450 loader was a little weak on bucket roll back power so I moved the bucket pins a few inches farther apart.( I still believe the original 5" between the bucket pins is not enough).
I've moved a lot of material over the past year of so and the loader has been working good..
Can't help you on the KB2375 backhoe.
I run a Rhino 85 backhoe w/subframe (8 1/2' digging depth, 11" reach) on my DK 35 and I have been very pleased with it.
If you can I recommend you go with an 8 1/2' backhoe.