The buzz word search has its limitations. The patent office is not a buzz word system. Its more of a dewy decimal system or classification system.
Add to this that Patent Agents have a tendency to speak in 'patentese' instead of plain daily language and the buzz word search can be even further limited. I doubt any of us would consider searching;
'appartus for the redistribution of particle matter over a planar surface'
No, Im pretty sure the majority of us would type 'broom'.
Formal Patent Searches are generally done by specialists. There is no designation for a 'Search Agent'. They are generally people who had heavy research backgrounds and somehow fell into it. Most law firms will sub the search work out to these individuals.
Formal Searches will range in cost from $700 to $1,500 per country. Many law firms add a review and report to the results at extra cost. The search itself is generally on the lower end of the cost range. The review and reporting being extra.
When I work with inventors, we need to make an effort to postpone costs as much as possible. Generally, we like to use our resources to see some level of success quickly. With this in mind, my clients andI found it more economical to perform the search with no review initially. The results will likely fall into one of three catagories;
1. 40% will be a clear 'no chance of obtaining patent protection'.
2. 40% will indicate patent protection is very possible.
3. The remainder will fall into the gray zone.
In the event of item 3 we will turn the file over to the Patent Agent/Attorney for review and pay the extra cost.
Probably a drawback of the internet is that anyone can do an online search. Make sure the search agent is not simply doing the same search you can do yourself. If the fee is too small, its likely the case.