Please can somebody post details of a book or link where an SEO expert says .pro is terrible for ranking. I have read several books on SEO and they all say the same thing, extension doesn't matter. The only time it matters is for geos, having a geo ending makes it harder to rank on the non-geo versions of search engines. I have never heard any SEO expert say .biz ranks ahead of .mobi, or .org ranks ahead of .info because it isn't trust. Backlinks, content, domaining ageing, site structure and tagging matters, extension doesn't.
Armed with that information, .pro starts to look appealing, it's a gTLD with no search engine geo bias, it was launched in 2004 and the top domains were regged in 2005 so it's going to be more aged than any new gTLD, and it's more appealing from a branding angle than .biz, .mobi, and .info. There are 15,000+ US trademarks that include the word "Pro", that's more than virtually all other extensions put together, put in allinurl(colon)pro.com in Google to see Pro branding appeal in .com.
Comparing .pro with .travel is illogical because travel is a keyword, pro is a branding suffix so Pro is more suited for bolt on use as a domain name. Pro is also shorter and snappier. RegistryPro are due to renew their management contract with ICANN in May 2010 and I'm hoping they will scrap the residual restrictions, their marketing has been dire but they signed up to a terrible business model 5 years ago and so they didn't have any money to spend on .pro. I think they have learned their lesson after losing money for 5 years and it will be difficult to ICANN to get anybody to run .pro with restrictions now the exclusivity of running a gTLD is going to disappear. gTLD's will compete on age and brandability and .pro is a front runner on both fronts.
I have been negotiating on the sale of 3 .pros this week. I agreed a sale of a .pro at 5,000 Euros on Sedo yesterday. With one of the other potential sales, the buyer is a French company with 40 employees, they have a domain in the format Keyword-Pro.fr and they are looking to upgrade to Keyword.pro, the buyer acknowledges that Keyword.pro is more brandable than Keyword-Pro.fr. A couple of weeks back, I sold Switch.pro for $2,000 to a Japanese buyer, he was a lighting engineer and designer, the site is already live.