I find DomainScore and Estibot very useful. I don't base .pro buying decisions on either but they are nice tools for a quick second opinion. Some of my favourite .pros don't do well on DomainScore or Estibot. For example, Studio.pro scores 458 and Salon.pro comes in even lower at 442. Estibot values Studio.pro at $450, I paid $3,000.
I like DomainScore and Estibot because they flag up what I may have missed. For example, if it wasn't for DomainScore and Estibot I probably wouldn't have bought France.pro, Italy.pro and Spain.pro. They scored very well so I did some more research and found that France, Spain, and Italy were the 1st, 2nd, and 5th most popular tourist destinations, collectively accounting for 20% of all 900m tourist visits globally in 2007 so as geos they take some beating.
DomainScore is very handy for objective ranking. For example, out of my favourite working environment .pros, Office.pro, Studio.pro and Salon.pro, they rank them 1) Office.pro, 2) Studio.pro and 3) Salon.pro which I agree with.
Out of France.pro, Spain.pro and Italy.pro, France.pro has the highest DomainScore total at 536, France is the only country of the three that is spelt the same locally and internationally, it is 3-4 times more popular in Google indexed URL's than Spain and Italy, and has 40% more visitors per annum than Spain and 85% more than Italy so the ranking is accurate.
Ship.pro is interesting, I bought Boat.pro from Vincent but I left Ship.pro in port. I figured people might buy a boat online but a ship implies something b2b rather than b2c and I wasn't convinced it would work. If somebody could make it work, there is a huge price tag at stake. Ship.pro would also make an excellent shipping transportation business name but you need to market something like that to a specialist company rather than a domainer.