The only one that I work with is Clear Evaluations. My fees have been paid on time and in full. I think, but am not sure, that I get paid for video shops at the end of the month following acceptance of the shop. With video, acceptance is usually 3-4 days after I submit the video and the (short) written report. I have never done anything but video for them, so cannot comment on their other shops.
I know the owners, and the extended family, for this company, and trust them completely. They are exceptionallly supportive and user friendly.
Based in MD, near DC
Shopping from the Carolinas to New York
Have video cam; will travel
I have had good luck with ISC too....the only thing i don't like is they don't have a job board...you have to just watch for emails...but I have been paid and I'm thinkging within a month....they have nice bonuses too.
With regard to what Walesmaven said about Clear Evaluations, I concur 100%. I'm not certain about the other two companies that you mentioned. I will say that Clear's payment schedule is noted in their ICA, and I have to imagine that the other two companies have theirs listed in that document as well. I would check that out if you have the time.