OK, so you are looking primarily at loader capacity. The 45 does have greater capacity. If I remember correctly the Deere 430 lifts about 1000 lbs 19 inches infront of the pivot point and the NH16LA lifts about 1500 measured at the same point. (NH's claimed 2000 lbs is at the pivot point - you have to keep apples to apples and choose to look at either the pin capacity or the middle of the bucket)
The 16LA is also a curved loader which may give you greater visibility. That's one of those personal preference questions.
While I like the Deere 4310, IMO they dropped the ball on the loader arms. The NH curved arms are easier to work with. I did find the cycle time was slower on the NH (I was using a TC40) than on the Deere. I don't know why.
You can get the NH 16LA loader on a TC35 or 40. It lists the same capacities and may bring the price under your budget. A quick look at an internet dealer site indicates you can get a TC35DA (hydro deluxe) with 16LA for between 19K and 20K. Add a grand to get the TC40DA. (Please note I am an advocate of buying from your local dealer who will service your tractor, even if it costs a small amount more than an out of state dealer; the service will make up for a reasonable price difference) Also, don't fall into the "no sales tax" hype. Search this site for the threads discussing that topic.
If you can still get 0% financing I would go with one of those over the used machine. Remember that even if you have 19K in cash, investing it in a tractor and pulling it out of where ever you have it costs you something in lost interest. 2% 3%? more? If you have to borrow it it will cost you even more. Prime is at 4.5% In my mind 0% financing of 19K for 3 years would be worth $1,500 to $2,000. That brings the effective price of the new TC35 down to 17-18K compared to buying used without financing
The warranty has to be worth a few thousand in peace of mind alone. Figuring in financing and warranty and I would go for a TC35DA or 40DA instead of the used machine.
Of course, your best idea might be to rent a real excavator when you need it and buy a tractor suited to your long term needs.
I rent a
chipper every spring and fall. If I was to buy one I would spend at least $5K. The unit I rent is bigger than anything I would buy and costs me about $150 for a weekend. I'll go visit my friends at the rental yard a few times a year and let them maintain it.
I don't have any experience with the other brands you mention. Good luck with the search. I'm sure you will be happy with whatever you choose.