Your opinions about KOETSU URUSHI BLUE or VERMILLION

@theophile  No big surprise. The build quality of Koetsus are nothing special. They also require a very heavy tonearm. The ART20 probably suites his tonearm better. If I were to get a stone body Koetsu I would put it in a 4 Point 14 which means I would have to buy another table. Not happening.  There are many cartridges that are better than the ART 20. The ART 20 is a great cartridge for the money assuming it is built well. I have not been able to look at one but I have looked at other AT cartridges and their quality control can fail on occasion.  When I say looked at I mean examined under both low and high power magnification with special lighting. I look at SRA under load, and stylus quality and mounting. It is much easier to mount and align a well built cartridge and the fact that a cartridge is well constructed is very reassuring.

tkr, it is that euphoric quality that some of us love about the Koetsu's. You would have to add a lot of weight to the SME V to get the bass right.
I use my Koetsu for string quartets and the like not for R+R and rarely for Jazz. The other cartridges I use are more neutral and to my ear more accurate not to mention better trackers (more accurate is not equal to better sounding.) 
mulveling, I certainly can not argue with your opinion. The FR's are certainly heavier arms. I would never use a Koetsu in a uni pivot arm. Actually, I would never use anything in a uni pivot arm so I guess that is not saying much. 

Mulveling, The Rosewood Signature Platinum weights 3 to 4 grams less than a stone bodied cartridge and requires a heavier tonearm to get the same bass impact. Bass and "impact" are the two most sensitive characteristics of a cartridge, the easiest to mess up. Resonance tuning is a real issue here. I think a lot of people miss out on it because most systems just do not go down that low. Not trying to insult anyone but it is hard and expensive to get a speaker/room to go below 40 Hz effectively. I had to build my own house to get it right. Anyway, the RSP bops just fine if you get that resonance frequency down under 10 Hz. I have never compared it directly to a stone bodied unit but the motors are the same and the only real difference is the mass of the cartridge which can be compensated for. Trying to put a stone bodied Koetsu in an arm as heavy as the 4 point 14 would be asking for it. The arm would go airborne with the first warp. I believe the stone bodies came along to make the cartridges perform better in the lighter tonearms that most of us use which are compatible with the majority of cartridges that are of medium compliance.
Chakster, they charge that much because they can get away with it. There are also several middle men. I think Ortofon has much better quality control. My Ortofon Windfeld Ti will track circles around my Koetsu and is by all accounts more neutral. 

Koetsu's may vary a little one to another even of the same model. then there is the set up and toenarms used. The paint used has absolutely no influence on the sound. 
Mulveling is right! I did not know this but the Vermillion has a different coil and is lower output so the phono amp is going to have to be a very quiet one or an SUT will have to be used. It might be a little more detailed due to the lighter coil but might not be a punchy for rock and roll.
Andy, you can add weight to your tonearm and it will work but you will never have the best bass a Koetsu can produce because you have a unipivot arm. These arms work better with more compliant cartridges. I can highly recommend the Ortofon Windfeld Ti cartridge. It will track anything and is a great rocker. It is about the same price as the Koetsu and should not require adding any weight to your arm. There are also cartridges from Clearaudio and Lyra that would work although Lyra recommends against using unipivot arms with their cartridges.

Andy, Koetsu's have nice warm bass if you put them in the right tonearm.
They are very stiff cartridges and require a tonearm with a high effective mass on the order of 18 to 20 grams. If you put them in a tonearm that is too light the bass will get rolled off and you might develop feed back. 
You can make a light tonearm work by adding head shell weights. In order to get this right you will need a test record like the Hi Fi News test record which has resonance bands on it. You add weight under you get the resonance point below 10 Hz but above 8 Hz. 
Which one to buy? Which color do you like? They sound exactly the same. My favorite Koestu is the Rosewood Signature Platinum. I use mine in a Kuzma 4 Point 14 which has an effective mass of 19 gm. The stone cartridges will work nicely in a lighter tone arm because they weight much more than the wooden cartridges.