I know this has been done to death, kind of. But there's been a discussion ongoing today on the ICB forum about it. A few folk are saying they would never go for fixed price but I've not really read any real arguments for hourly rate.
I am genuinely interested to know, if you do hourly rates and would never think about fixed price, why? What are the pros of hourly?
I think it can save a lot of hassle if the client decides s/he wants "extras" from the agreed service. If on an hourly rate these can be accommodated without negotiating an increase to fixed fee, as a letter of engagement won't necessarily cover all eventualities. It's far easier to add extra hours to your invoice then get into a convoluted discussion of what is and is not included in fixed fee.