As far as cabinets go, I do not believe that there is any best with the JMP, there are only different options. The 1960 cabinets are always popular because they match, but there are a ton of possible boutique cabinets, including StoneAge and Bogner, that sound excellent. The most important consideration when deciding which speaker cabinet is right for you is probably going to be the speakers themselves. If you are playing rock or older metal (NWOBHM/thrash), speakers such as Greenbacks or G12-65s would work very well. I have also heard great things about Vintage 30s with the older Marshalls, and you can even start looking into doing an x-pattern cabinet with different speakers, such as Vintage 30s and G12-T75s. There are even boutique manufacturers such as Scumback that make excellent modern production speakers.
1960 cabs are ok. I have some with Vintage 30's which would be the 1960V series and those are really cool. I've had the Vintage 30's for a long time now and it's taken a year for them to really grow on me. The more I jam through them the more I'm leaning away from G12T-75's which are in the 1960 cabs. Those V30's can be a bit harsh at times, a mix of 75's and V30's can be pretty cool as well.
As far as cabinets go, I do not believe that there is any best with the JMP, there are only different options. The 1960 cabinets are always popular because they match, but there are a ton of possible boutique cabinets, including StoneAge and Bogner, that sound excellent. The most important consideration when deciding which speaker cabinet is right for you is probably going to be the speakers themselves. If you are playing rock or older metal (NWOBHM/thrash), speakers such as Greenbacks or G12-65s would work very well. I have also heard great things about Vintage 30s with the older Marshalls, and you can even start looking into doing an x-pattern cabinet with different speakers, such as Vintage 30s and G12-T75s. There are even boutique manufacturers such as Scumback that make excellent modern production speakers.