Which Burr should I buy?

Standard Burrs

Italmill Burr - Made in Italy. Similar performance to New SS burr.
Titanium Italmill Burr - Made in Italy (5-10x more durable than standard italmill)
New Stainless Steel Burr - New shape and rust proof.
DLC Stainless Steel Burr - Diamond Like Carbon (DLC). Burr stays sharper longer. 5-x10x more durable than SS burr.

SSP burrs will give you the best grind quality given it's precise burr shape and material.

SSP High uniformity (Espresso) is best suited for your espresso needs, best body, balance and highest extraction

SSP Cast burr (Lab Sweet) is recommended if you like acidity and sweetness over body. 

SSP Unimodal Espresso (Multipurpose) produces a range of fines, good for a big range of flavour and overall aroma and flavour for filters and espresso.

COATINGS
Silver knight coating has almost same specification as Red speed. Though performance is similar, some users feedback there is big difference. Silver knight has little bit lower coefficient friction value than Red speed. 

ITALMILL STANDARD BURR (SILVER)
TITANIUM ITALMILL STANDARD BURR (GOLD)
NEW STANDARD BURR (SILVER)
Standard burr 64mm DF64
DLC BURR (BLACK)
 DLC 64mm burr
SSP ESPRESSO BURR 
SSP MULTIPURPOSE BURR 
SSP CAST LAB SWEET BURR (RED OR SILVER)