The best meshing experience is with adapters that have good signal power and sensitivity, and a good implementation of the 802.11 Ad-Hoc (technically called IBSS) mode. Please note that in IBSS mode your adapter must maintain connections with all neighboring nodes (while in Infrastructure mode it always communicates only with the AP), so, your adapter's chip must be powerful enough to handle that load.
Also please note that adapter range depends not on the adapter alone, but in pairs with other adapters it has a link with. Combination of one's power and another's sensitivity. We offer a 30-day trial so you can test in your particular case.
We have a poll where you can vote for the WiFi chipsets that your adapters have, so we can keep an eye on the most widespread chipsets and test them in our lab. Please visit and vote.