For me personally the best performance machine would be the TDI Pro,possibly the last one that was sold in the UK before the battery ban stopped sales,regarding best sales model that i cannot say as alas i dont buy Whites VLF machines anymore,have always been a ardent diehard Whites fan but although i do own 3 VLF machines and wont ever part with them they just dont produce any machines anymore that i would buy.
But my vote would go for the TDI Pro and even that has stopped production in favour of the 'sl' version,just my opinion of course but sales here in the UK of the companies products have dwindled in the last 5 years this is from observation from weekly club digs and rallies.