You are looking at two totally different types of tractors. The
B3030 is an ultralight machine the CK30 is a heavyweight. In fact, so far as I can tell there is no lighter weight tractor on the market than the
B7800/
B3030 class machine. The CK30 is on the other end of the weight spectrum and is a half a ton heavier. These machines may both have 30hp engines but there is nothing else similar about what they are designed to do and what they are capable of doing.
The
B3030 is going to be great as a lawn machine, it excels with a 72" Mid Mount Mower, its light weight is much less likely to rut. It is also physically much smaller, being about a foot and a half shorter in length. It is a GREAT machine for light to medium landscape chores around the house. It would be marginal, but capable of doing heavy work. It is a breeze to trailer with a standard duty truck or SUV on a standard trailer. I see lots of commercial landscape crews using Kubotas, the guy who owns the service I deal with is a friend of ours and they like them because of the light weight not destroying customers yards they are working in and for ease of trailering.
The CK30 does not currently have a MMM at all so if mowing is one of the possible tasks, it is certainly the weaker candidate. However in terms of shear capacity, the 130 loader on the CK is a powerhouse compared to the
B3030's loader. 3pt hitch capacity is also substantially higher on the CK. In terms of tasks it will excel in the heavy duty jobs but will be marginal in the light duty jobs. The extra weight is great if you are doing a lot of ground engaging, but of no real benifit if you are PTO powered equipment like a PHD or finish mower. Heavier tractors use heavier attachements, you may find that trailering will require a HD truck, which may or may not be any consideration.
I can't speak to the BH on either brand.
I would strongly suggest you consider your long term tasks very carefully and pick the TYPE of machine that is better suited to tasks you plan to do with the machine.