Ask HN: What experts or tools can you recommend for usability testing?

I have been working a startup in the travel sector for the past few years. I am finally a bit freed up from the development grind, and traffic has reached a point where just even small increases in conversion percentages make it very worthwhile focusing on UX enhancements and usability testing.<p>The site is about 5,000 pages, and what I am looking for is in-depth expert analysis of a few critical points in the flow where I know there is vast potential for improvement.<p>I have looked at a few of the tools including:<p>http://feedbackarmy.com http://www.loop11.com http://www.trymyui.com http://www.usertesting.com<p>Does anyone have experience with these tools or others? My feeling is that it may be better to hire a usability/UX expert to weigh in - a fresh set of experienced eyes to spot some obvious things.<p>I am open to any and all input.