Jim,
Ive been doing alot of looking at different backhoes for my 3130 also. Ive decided that sticking with a Kubota product is the way to go so for me it's come down to either the BL4690B or BH90. The best prices Ive gotten so far are $6100 for the 4690 w/reversable feet and $7800 and remotes for the 90, both installed. My dealer is pushing the 4690 for my needs and tractor. He says he's had real good luck with them, no complaints and he just feels the the 90 is oversized for the 3130. I drove an extra hour past the closest Kubota dealer to buy my tractor from this guy because I trust him and he hasnt lead me astray yet so I do have some level of trust in him. It seems that most here are pushing for the BH90 and for good reasons. I guess Im still on the fence.
There are alot of other good hoes out there and the water really atarts to get murky when you include them in the possibilities. I was actually relieved when I made the decision to stay with Kubota. I was getting a headache thinking and reading about BushHog, Bradco, Woods, LandPride, the list goes on. The reason that I've decided on Kubota has little to do with quality, there are other hoes that I believe are of good quality, it has to do with service and warranty (mostly of my tractor). I wish I could give you some real world experience with these hoes but at the moment Im still looking for the right answer myself. Let me know how your search goes, as Im still trying to decide which hoe is for me.
As for whether you need a 3430 over a 3130. I dont think there is any differnces. Basically the same weight, size and hydraulics. There arent really any differences until you get up to the 4330. My dealer says he suggests the BH90 for the 4330 and bigger based on the increased weight and more GPM. thats just his $.02 for what its worth.