I think all went quite well, but there a few things worth sharing:
We spent quite a lot of time researching the s/h market to see what was out there. The wide range of small manufacturers with lots of designs made comaprisons difficult, but at least we got an idea of what we wanted in terms of layout and specification. Of course if we had opetd for brand new we would hace been in a position to specify what we wanted, but at a significant premium. We decided to buy s/h, accepting some compromise in design and use this as a 'trial' boat to see what features we really want.
I would thouroughly endorse the need for a survey unless you have sufficient expertise and confidence in outboards and GRP! However you should also be aware of the limitations of a survey; like a house survey it will identify issues but not necessarily root causes. We have some electrical/electronic snags which are more difficult to resolve than the assumed 'replace bulb' and 'change settings' assumptions. This is, however, in no way a criticism of the surveyor who was very thorough.
I terms of process, I combined the survey with a test drive which allowed the surveyor to see the boat working. I had to pay a small fee for the test drive (this is farily standard practice to cover fuel and lifting costs) but this was deducted from the purchase price. As I only tested one boat this did not become a financial burden. I was required to make a verbal offer before the test drive, but did not feel pressured to commit to this if the survey had identified serious flaws.
Overall, not too difficult. The RIB world felt very friendly, probably as a consequence of being made up of a lot of small operations rather than larger corporates.
I hope this helps, good luck and see you on the water!