I have been dealing with Balsa Central for a number of years and found both their service and quality of their balsa/ply to be extremely good.
Aeromodelling supplies have declined over recent years with many preferring to buy ready made models. Consequently it has become difficult to get a range of sizes especially thicker block. Although I prefer to hand select balsa I have found Balsa Central has been able to accurately supply my requested weight and grain preferences. It arrives beautifully packed and on time.