I think you are looking at some different types of tractors.
The TC30 is an old style bare bones tractor, it is not in the same league as the Kioti CK30. The TC30 is also fairly small when you compare it to the Kioti. For the same reasons you might eliminate teh JD790, you would likely eliminate the TC30.
A better comparison would be the TC29 or the TC33. Both of those are deluxe tractors, but both are also more expensive and may not be price competitive. The TC29 and TC30 are both 30hp tractors, but they are radically different machines! My opinion is that the likely Kubota to consider would be the
L3130 with the 723 loader.
I know little about the Mahindra.
As far as loaders go here is a run down on the various Kubota, NH and Kioti units for the above mentioned tractors:
Kubota 723 on the
L3130:
Breakout force: 2605#
Lift capacity: 1870
Lift Height: 8'6"
New Holland LA14 on the TC29 or TC33
Breakout force: 2712#
Lift capacity: 1256#
Lift Height: 8'2"
Kioti 130 on the CK30
Breakout force: 2046#
Lift capacity: 1155#
Lift Height: 7'9"
Breakout force, lift capacity and lift height are all measured at the bucket pivot point, not at the bucket edge. OTHER THAN PRICE, consider what you are going to do with the tractor. IF you are planning on doing a lot of Front End Loader work, then the advantage actually leans pretty heavily towards the New Holland because the curved loader arms and curved hood make it easier and faster to do loader work in the real world. The Kioti would probably be my second choice for loader work for the same style of loader, despite the fact that of the above 3 tractors it has the weakest loader. I use a NH and a Kubota and I have to tell you that the NH curved loader arms and curved/sloped hood allow excellent visibility of the bucket, the Kubota (and very likely the Mahindra) have traditional long flat hoods and squared off dog-leg style loader arms that dramatically limit forward visibility. People who have never used the new curved style loaders simply cannot understand how much better/quicker work can be done until they try it. Having 2 different machines of similar capabilities, I can use them side-by-side and I can attest to the fact that you can't compare them, I can do more work in less time . . . and isn't saving time one of the reasons we buy tractors?
CHANGING USES and considering something as mundane as mowing the lawn, I would suggest that you want the smallest and lightest tractor for that use if you have clay soil. If you have sandy soil then weight is less imporant, but turning radius is still a large consideration. The tighter the tractor turns the faster you lawn will be mowed (tighter turning radius is also beneficial for loader work). As you don't say what you are using the tractor for, I'm just trying to cover some of the bases.
Please reconsider your choices. You need to understand that different tractors are designed for different types of uses. The JD790 and the the NH TC30 are similar types of machines for similar users. The CK30 is in a different class, and should be compared to the TC29 or TC33. Again, I know little about Mahindra other than what I see on their website, I honestly don't know where that tractor falls in terms of use. People here might be able to give better advice if you tell us what you plan on using the tractor for, and what the biggest tasks will be (hours per week) versus the smaller tasks as a % of the total time spent. That will help us guide you to a particular class of tractor. You have no information in your profile, we don't know how many acres you have, so these machine may be way too large or way to small for you. We have no idea your intended use, nor your climate, etc. I think you'd find more specific information can come from the members if you fill out your profile with at least some basic information.
