WDS versus Backbone network

If I have the option to link a three AP (A1, B1, C1) network with backhaul radio’s (A2<>B2<>C2 where A2<>C2 is unlikely due tree/hill) or have the three AP’s just on WDS-mash and use the 2nd radio’s for extra AP’s. What would be the best option?

Each location will have to serve 10-50 clients for max. 2Mb internet access only.

All three units are dualradio’s. If WDS works as good as a seperate backhaul network (that will be bridged on each unit to the twin radio) then I might leave it and us the 2nd radio’s for better signal coverage over clients with sector antenna’s?

Distance 500 and 700 metres between AP locations.