Go ahead and get the real filter from Kubota - in the long run you may have paid a couple or bucks more BUT you will have peace of mind knowing that it fits and does the intended job.
Here's my take on this topic, and for the record, I don't think I've ever suggested that Kubota filters are the best choice, but they are the only guaranteed choice.
There are no industry standards for oil or hydraulic oil filters as there are for engine oils and other automotive related items such as engine coolant. In the case of engine oil, as long as the oil that you use meets the requirements listed by Kubota in the owner's manual then all is good. But there are no requirements or specifications listed for filters so how do you know that you're buying an equivalent product?
How do you know that your choice of non-Kubota filter meets Kubota standards? You can bet that Kubota has filters made to their requirements or standards regardless of who makes them, or where they're made. When you buy a Kubota filter you know that it's got Kubota's stamp of approval but that's not the case for other brands, that might actually be better, or a lot worse. If the cost difference were huge I might be looking for alternatives, but since it's not, I buy Kubota filters which are readily available just 3 miles from my house. When the dealer moves much closer to the center of town later this year, I will still buy Kubota filters, but not because I know or think of them as being superior, but simply because there is no doubt that they meet Kubota requirements for flow rate, particulate size, longevity and integrity.
For those that use other brands, what's the flow rate and micron filtration rate of your choice of filter, and how does it compare to the equivalent Kubota filter? Also, how does the filtration media in other brands react over time when exposed to UDT or UDT2? I would expect Kubota to have tested for these kinds of variables but can the same be said for other manufacturers?