kelago,
I was where you are a year ago, except I couldn't read the French. You already know the words. Next, you make believe you know what they mean, and after that you give other people advice.
Your decision on a belly mower should help answer your question. If you want a belly mower, you have to go 3ph hoe. Belly mower on 3010 means it will not be fun to take off and on, and you will be limited to turf tires. If you dont care about belly mowers, I would go with a subframe backhoe over the 3ph. If I had the money I would buy the Bradco 408. If saving money is important, I would get the Woods direct attach over the Kubota. Maybe up to $1000 cheaper for an equivalent hoe. Plus you can resell a Woods hoe to anyone; a Kubota hoe's resale potential is limited to Kubota tractors.
If backhoes and belly mowers are important to you, you really should look at the JD 4300 and 4400. Their 48 backhoe is the easiest of all to remove and install, specs out significantly higher than the Kubota 4690 or the Woods 7500, and is completely compatible with a belly mower.
Just some more Chinese to overpopulate your mind.